Air return duct

Air return duct systems can be configured in two ways: each room can have a return duct that sends air back to the heating and cooling equipment, or return grills can be located in central locations on each floor. For the latter case, either grills must be installed to allow air to pass out of closed rooms, or short "jumper ducts" can be installed to connect the vent in one room with the next, allowing air to flow back to the central return grilles. Door undercuts help, but are usually not sufficient for return airflow.

You can perform a simple check for adequate return air capacity by doing the following:

1. Close all exterior doors and windows
2. Close all interior room doors
3. Turn on the central air handler
4. "Crack" interior doors one by one and observe if the door closes or further opens "on its own." (Whether it closes or opens will depend on the direction of the air handler-driven air flow.) Rooms served by air-moved doors have restricted return air flow and need pressure relief as described above

DESIGNING AND INSTALLING NEW DUCT SYSTEMS

DESIGNING AND INSTALLING NEW DUCT SYSTEMS

Efficient and well-designed duct systems distribute air properly throughout your home without leaking to keep all rooms at a comfortable temperature. The system should provide balanced supply and return flow to maintain a neutral pressure within the house.

Even well sealed and insulated ducts will leak and lose some heat, so many new energy-efficient homes place the duct system within the conditioned space of the home. The simplest way to accomplish this is to hide the ducts in dropped ceilings and in corners of rooms. Ducts can also be located in a sealed and insulated chase extending into the attic or built into raised floors. In both of these latter cases, care must be taken during construction to prevent contractors from using the duct chases for wiring or other utilities.

In either case, actual ducts must be used -- chases and floor cavities should not be used as ducts. Regardless of where they are installed, ducts should be well sealed. Although ducts can be configured in a number of ways, the "trunk and branch" and "radial" supply duct configurations are most suitable for ducts located in conditioned spaces.

living area.

• living area.
• Be sure a well-sealed vapor barrier exists on the outside of the insulation on cooling ducts to prevent moisture condensation.
• If you have a fuel-burning furnace, stove, or other appliance or an attached garage, install a carbon monoxide (CO) monitor to alert you to harmful CO levels.
• Be sure to get professional help when doing ductwork. A qualified professional should always perform changes and repairs to a duct system.

MINOR DUCT REPAIR TIPS

Although minor duct repairs are easy to make, qualified professionals should seal and insulate ducts in unconditioned spaces to ensure the use of appropriate sealing materials.

MINOR DUCT REPAIR TIPS

• Check your ducts for air leaks. First, look for sections that should be joined but have separated and then look for obvious holes.
• Duct mastic is the preferred material for sealing ductwork seams and joints. It is more durable than any available tape and generally easier for a do-it-yourself installation. Its only drawback is that it will not bridge gaps over ¼ inch. Such gaps must be first bridged with web-type drywall tape or a good quality heat approved tape.
• If you use tape to seal your ducts, avoid cloth-backed, rubber adhesive duct tape -- it tends to fail quickly. Instead, use mastic, butyl tape, foil tape, or other heat-approved tapes. Look for tape with the Underwriters Laboratories (UL) logo.
• Remember that insulating ducts in the basement will make the basement colder. If both the ducts and the basement walls are not insulated, consider insulating both. Water pipes and drains in unconditioned spaces could freeze and burst if the heat ducts are fully insulated be-cause there would be no heat source to prevent the space from freezing in cold weather. However, using an electric heating tape wrap on the pipes can prevent this. Check with a professional contractor.
• Hire a professional to install both supply and return registers in the basement rooms after converting your basement to a 

Your air ducts are one

Your air ducts are one of the most important systems in your home, and if the ducts are poorly sealed or insulated they are likely contributing to higher energy bills.

Your home's duct system is a branching network of tubes in the walls, floors, and ceilings; it carries the air from your home's furnace and central air conditioner to each room. Ducts are made of sheet metal, fiberglass, or other materials.

Ducts that leak heated air into unheated spaces can add hundreds of dollars a year to your heating and cooling bills. Insulating ducts in unconditioned spaces is usually very cost-effective. If you are installing a new duct system, make sure it comes with insulation.

Sealing your ducts to prevent leaks is even more important if the ducts are located in an unconditioned area such as an attic or vented crawlspace. If the supply ducts are leaking, heated or cooled air can be forced out of unsealed joints and lost. In addition, unconditioned air can be drawn into return ducts through unsealed joints

VENTILATION FOR COOLING

VENTILATION FOR COOLING

Ventilation for cooling is the least expensive and most energy-efficient way to cool buildings. Ventilation works best when combined with techniques to avoid heat buildup in your home. In some climates, natural ventilation is sufficient to keep the house comfortable, although it usually needs to be supplemented with spot ventilation, ceiling fans, window fans, and—in larger homes—whole-house fans.

Ventilation is not an effective cooling strategy in hot, humid climates where temperature swings between day and night are small. In these climates, however, natural ventilation of your attic (often required by building codes) will help to reduce your use of air conditioning, and attic fans may also help keep cooling costs down

WHOLE-HOUSE VENTILATION

WHOLE-HOUSE VENTILATION

The decision to use whole-house ventilation is typically motivated by concerns that natural ventilation won't provide adequate air quality, even with source control by spot ventilation. Whole-house ventilation systems provide controlled, uniform ventilation throughout a house. These systems use one or more fans and duct systems to exhaust stale air and/or supply fresh air to the house.

There are four types of systems:

• Exhaust ventilation systems work by depressurizing the building and are relatively simple and inexpensive to install.
• Supply ventilation systems work by pressurizing the building, and are also relatively simple and inexpensive to install.
• Balanced ventilation systems, if properly designed and installed, neither pressurize nor depressurize a house. Rather, they introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.
• Energy recovery ventilation systems provide controlled ventilation while minimizing energy loss. They reduce the costs of heating ventilated air in the winter by transferring heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer, the inside air cools the warmer supply air to reduce ventilation cooling costs.

Natural ventilation

Natural ventilation is unpredictable and uncontrollable—you can't rely on it to ventilate a house uniformly. Natural ventilation depends on a home's airtightness, outdoor temperatures, wind, and other factors. During mild weather, some homes may lack sufficient natural ventilation for pollutant removal. During windy or extreme weather, a home that hasn’t been air sealed properly will be drafty, uncomfortable, and expensive to heat and cool.

SPOT VENTILATION

Spot ventilation can improve the effectiveness of natural and whole-house ventilation by removing indoor air pollution and/or moisture at its source. Spot ventilation includes the use of localized exhaust fans, such as those used above kitchen ranges and in bathrooms. ASHRAE recommends intermittent or continuous ventilation rates for bathrooms of 50 or 20 cubic feet per minute and kitchens of 100 or 25 cubic feet per minute, respectively

VENTILATION STRATEGIES

VENTILATION STRATEGIES

There are three basic ventilation strategies—natural ventilation, spot ventilation, and whole-house ventilation.

NATURAL VENTILATION

Natural ventilation is the uncontrolled air movement in and out of the cracks and small holes in a home. In the past, this air leakage usually diluted air pollutants enough to maintain adequate indoor air quality. Today, we are sealing those cracks and holes to make our homes more energy-efficient, and after a home is properly air sealed, ventilation is necessary to maintain a healthy and comfortable indoor environment. Opening windows and doors also provides natural ventilation, but many people keep their homes closed up because they use central heating and cooling systems year-round

Ground source heat pumps

Ground source heat pumps All analyzed heat pump systems are installed in German single family houses with floor heating. The heat pump is more or less monovalent, only a very small amount of backup heat has been used during the year of measurements. The heat pumps in the study were all  installed in new built houses during the years 2004-2008.  The data used for the SPF calculations are based on field measurements carried out during one year, with one exception the SPF for site no. 1 is based on data measured from January to August.
The calculations of SPF’s are based on the field measurements data from the Fraunhofer study. In the data we have received from the Fraunhofer study the total energy consumption for the heat pump system and its components is presented as well as the energy consumption divided into energy used for space heating and energy used for production of domestic hot water

In this project

In this project we have not been able to evaluate exactly how these allocations have been made. For some of the studied installation sites a part (up to 20%) of the total electricity consumption has been allocated neither to space heating nor to the domestic hot water production. This is mainly the case for the electricity consumption. For the heat produced no energy gap is seen between the total energy production and the energy divided into space heating and domestic hot water.  
The calculated SPF’s in the study are based on the energy allocated to the space heating only, this in order to make the results comparable to the results from the calculation models in prEN14825 and Lot 1, which not include the production of domestic hot water.
Air to air heat pumps The field measurement of the air to air heat pumps is carried out in single family houses located in the Borås area of Sweden. All houses in the study have electricity driven radiators for back up heating.  The field measurements are based on SP method 1721. From the field measurements SPF2 and SPF3 has been calculated as described below.

The electricity consumed

The electricity consumed by the heat pump, WHP, is measured continually while the produced space heating is measured at five “performance tests” done at different outdoor temperatures. During the performance tests the heating capacity of the heat pump is measured during stable conditions and is thereby not including any defrost period. Therefore the calculated COP for each test point is based on data from only a part of the operating cycle.  
The total amount of heat produced during the total measuring period needs to be calculated based on the five performance tests. The calculations are made as follows

Ground source heat p

Ground source heat pumps When using prEN14825, data according to Table 13 has to be filled in. The chosen climate, “average” gives that Tdesign is -10°C. Tbivalent is the outdoor temperature where the capacity of heat pump covers the heat demand of the house. It is set to -10°C, to make the heat pump monovalent, like in the field study. TOL, the operation limit temperature, is set to -25°C. This temperature declares where the heat pump no longer can operate. The model calculates Pdesign as a result of Tbivalent and is the heat demand of the house at Tdesign.

The test conditions

The test conditions for the heat pumps were taken from Table 20 in the standard, brine to water heat pump, average climate and low temperature application. The unit is assumed to be a fixed capacity unit with fixed outlet temperature. The heat pumps in the study where all tested in full load according to EN 14511. For the part load conditions the COP was calculated by using equation 12 in the standard. The test point used for the calculations was the 30°C/35°C point from EN 14511 laboratory data. The capacity and COP at Tbivalent and TOL is set to the maximum, while the COP for the delivered capacity at the different outdoor temperatures is calculated by using equations from the standard prEN14825. The default degradation factor where Cc=0.9 is used.

Air to air heat pumps

Air to air heat pumps The data for SPF calculations regarding air to air heat pumps are taken from the field measurements. There are no laboratory data available for the heat pumps tested in the field study.  
The colder climate is chosen for the calculations, since this climate is similar to the climate where the field installation is. The bivalent operation point of the heat pump is calculated by using SPA3528, which is another model for the calculation of SPF. The bivalent point is 0°C. The operation limit point is set to -20°C

the interpolation

At -7°C the heat pump operates in full load to deliver heat to the house. At +2°C and at +7°C the heat pump operates in part load. COP for part load operation is interpolated by using linear interpolation between existing test points. At +2°C the interpolation is made between full load operation and operation at 47% part load, at +7°C the interpolation is made between part load operation at 50% and 57% of the heat pump capacity. At +12°C the required heat load is so small that the heat pump is assumed to cycle on/off. The capacity of this point is calculated by using equation 11 in the standard. The COP for the bivalent point is interpolated from test points in full load operation at +2°C and -7°C

Constant Air Volume

Constant Air Volume System: An air-handling system
involving a continuous level of airflow.
Contact Vacuum: A Collection Device, usually portable,
that uses a nylon brush nozzle attached to the end of its
inlet air hose. The brush head is applied directly to a
surface for cleaning.
Containment Area: An engineered space within a work
area designed to control the migration of contaminants
to adjacent areas during assessment or cleaning
procedures.
Contaminant: Any substance not intended to be present
that is located within the HVAC system.
Converging 45 Degree Cut: Applies to the angle of the
cut when removing a section of ductboard to create an
opening. Provides for resealable fit when re-installing
the section for closure (sometimes referred to as a
“pumpkin cut”).

Hinged -

Hinged - fabricated door and doorframe attached
together with a hinge.
Sandwich - two-part closure device in which the two
sides are mechanically fastened together on both
sides of the duct wall at the perimeter of the service
opening.
Spin Door - round access door and door frame
installed by spinning the door frame into a round
opening.
Ductwork: A system of passageways for distribution and
extraction of air, excluding plenums not installed in
accordance with SMACNA Standards (See ASHRAE
Terminology of Heating, Ventilation, Air Conditioning &
Refrigeration, 1991).
EPA: United States Environmental Protection Agency.
Flame Spread Index: The Flame Spread Index refers to
the sustained combustion classification of a material as
listed in NFPA 255, Standard Method of Test of Surface
Burning Characteristics of Building Materials.

Accumulators should

Accumulators should be possible to include in the model.
 A model must contain clear system boundaries for what is to be included in the calculations and how measurements are performed. As a basis, the system boundaries presented in the SEPEMO project [12] is recommended.
 The model must be transparent so it is possible to follow and understand the calculations. The studied models all contain parts that are more or less transparent. For example how the estimation of the number of equivalent heating hours is performed is not shown in any method.

Crossbreak:

Crossbreak: Diagonal bends made in metal panels to
increase rigidity and decrease flexibility.
Debris: Non-adhered substances not intended to be
present within the HVAC system.
DOP Testing: The percentage removal of 0.3 micrometer
particles of dioctylphthalate (DOP) or equivalent used to
rate high-efficiency air filters, those with efficiencies
above 98%.
Double Wall Duct: Sheet metal duct usually constructed
with an inner perforated liner sandwiching fibrous glass
insulation.
Duct Access Door: Fabricated metal barrier (hatch) by
which a service opening is accessed or closed.
Designed for permanent installation. May be available
pre-fabricated in a variety of sizes and configurations.
Most utilize cam locks for securing the removable door
from the permanently installed doorframe. Types of
Duct Access Doors are listed below:

Biological Contaminants

Biological Contaminants: Bacteria, fungi (mold and
mildew), spores, viruses, animal dander, mites, insects,
pollen, and the by-products of these elements.
Cleaning: The removal of visible particulate and
biologicals to a level defined within this document.
Closure: (1) An access door or panel installed on the air
duct or air-handling unit to create a permanent seal. (2)
Device or material used in closing a service opening.
Closure Panel: Sheet metal, or other appropriate
material used for permanently closing a service opening.
Coatings: See “Surface Treatments.”
Coils: Devices inside an HVAC system that temper
and/or dehumidify the air handled by the HVAC system.
These include heat exchangers with or without extended
surfaces through which water, ethylene glycol solution,
brine, volatile refrigerant, or steam is circulated for the
purpose of total cooling (sensible cooling plus latent
cooling) or sensible heating of a forced-circulation air
stream (See ASHRAE 33-78 and ARI 410-91).

Air Scrubber

Air Scrubber: An air filtration device (AFD) using HEPA
filtration configured to re-circulate air within a defined
space.
Air Sweeping: A process that uses a pressurized air
source combined with either handheld blowguns or a
hose with a remote nozzle attachment to move
particulate and debris within an HVAC system during
cleaning.
ASCS: Air Systems Cleaning Specialist. The ASCS
designation is awarded by NADCA to industry
professionals who satisfactorily complete a written
certification examination testing knowledge of HVAC
systems, cleaning standards and best practices.
Ambient Air Cleaning: The process of removing
particulate from indoor air outside of the HVAC system

Air Duct Covering

Air Duct Covering: Materials such as insulation and
banding used to cover the external surface of a duct.
Air Duct Lining: Generally refers to fiber glass or other
matting affixed to the interior surfaces of the air ducts for
thermal insulation and noise attenuation.
Air Filtration Device (AFD): A portable or transportable,
self-contained blower assembly designed to move a
defined volume of air equipped with one or more stages
of particulate filtration. Depending on the mode of use,
an AFD that filters (usually HEPA) and re-circulates air is
referred to as an "air scrubber." One that filters air and
creates negative pressure is referred to as a "negative
air machine."
Air-handling Unit (AHU): A packaged assembly, usually
connected to ductwork, that moves air and may also
clean and condition the air.

Antimicrobial:

Antimicrobial: Describes an agent that kills or inactivates
microorganisms or suppresses their growth (See ASTM
E35.15)
Antimicrobial Surface Treatments: Chemical or physical
agent applied to, or incorporated into materials that
suppresses microbial growth.
Assessment: A comprehensive review and evaluation of
the HVAC system, or representative portions thereof, to
make a preliminary determination of which general forms
of contamination are present and to document the
overall system cleanliness level.
ASHRAE: American Society of Heating, Refrigerating,
and Air-Conditioning Engineers

An outcome

 An outcome of the results should be to see that a properly sized heat pump is the best alternative to install. An oversized heat pump will result in unnecessary on/off cycling losses and an undersized heat pump will result in unnecessary high back-up heating.
For the calculation, either BIN methods or hour by hour calculations could be used. The existing calculation models based on heat pump performance testing according to standards are all using BIN models. Therefore, to keep a clear connection to existing test standards, it is the easiest to base a new model on BIN models. A hybrid model using chronological BIN’s could also be an interesting option to look into.

The drawback

The drawback with this approach might be that dynamic effects, especially in cases with large or well stratified accumulators are not treated in a way that the full potential of these units are revealed. In the proposed IEA Annex, a thorough investigation of the positive and negative effects of these approaches should be performed

The possibility

The possibility to include the production of domestic hot water to the SPF calculations is also a necessity in future calculation models. It should also be described how this shall be measured in tests alternatively, how the amount of produced domestic hot water shall be estimated. Today there are two main ways how to do the measurements, including the losses or not (one can measure the amount of energy that is obtained by tappings or the amount of tap water the heat pump is producing). A lot of work has already been done in this respect in the IEA HPP Annex 28 [13]. Also, there is a CEN standard on the way on how to treat DHW production. This standard however does not take into consideration combined heating and DHW production.

For ground source heat pump

For ground source heat pumps, the temperature of the ground is varying during the year. The model should include a correction for this. This could be expressed as a function where the ground source temperature is a function of the outdoor temperature over the year.
 The model should contain a radiator heat curve where requisite supply temperature is calculated, an example of this can be found in the thesis of Fredrik
49
Karlsson [8]. At a colder outdoor temperature, the supply temperature should peak; this makes the test scheme tables in EN 14511 deficient. Also other heat distribution systems, such as under floor heating, and mixed systems should be included in the model

Point-source heating and cooling

Point-source heating and cooling

Ductless minisplit heat pumps are ideally suited for compact, highly energy efficient homes. Our house has R-values greater than R-40 in the walls and R-50 in the roof, plus very tight construction with a heat-recovery ventilator for fresh air. In tight, superinsulated homes, a single space heater (point-source heating system) can work very well, because with all the insulation fairly uniform temperatures are maintained throughout the house.

Completed installation.
Photo Credit: Alex Wilson

With our 1,700 square-foot house, the two upstairs bedrooms may stay a little cooler than the downstairs, but we like a cooler bedroom. In a larger house or one that isn’t as well insulated, several ductless minisplit heat pumps or a ducted heat pump option might be required.

To take into account

To take into account for the climate at the installation, generally accepted spot climate data, for example Meteonorm data [9], Should be a part of the model.
 The dynamics of the house can be a part of the model. The perceived temperature of the house is not fully consistent with the actual outdoor temperature. At colder temperature dips of for example -15°C, the house will not experience the real outdoor temperature, but experiences a temperature of -12°C instead (due to internal heat gains). Even the irradiance of the sun differs between the seasons (and different spots). The energy demand of the house is affected from those variances over the year, why it might be an idea to calculate the SPF over monthly periods. Also the use of a fictive outdoor temperature would be an alternative. The climate data can be adjusted (flattened out) depending on a number of inputs, but a temperature dip is still needed in order to make a proper effect dimensioning (this is dimensioning the entire system such as deep wells etc.). In a serious effort to evaluate dynamics, other factors have to e incorporated in a model, such as form factor, impact of building weight, window area compared to wall area, placement of windows, etc., which make such a model very complex

Our units incorporate eco-comfort technology, dual and triple-allergen filtration, and are whisper-quiet.

Our units incorporate eco-comfort technology, dual and triple-allergen filtration, and are whisper-quiet.

Eco-comfort technology makes these systems smarter in how they use energy and minimizes their impact on the environment. Plus, there are many advanced features like the i-see Sensor™ 3D, that automatically detects room temperature differences and adjusts for greater comfort. Mitsubishi Electric's advanced multi-stage filtration systems dramatically reduce allergens and help eliminate odors. Our indoor units operate with sound levels starting as low as 19dB(A), quieter than a human whisper.

Mitsubishi Electric offers the most technologically advanced heat pump systems in the world.

Unlike older, inefficient heat pumps, there is no cold air delivery with Mitsubishi Electric's Cooling & Heating systems. The Hot Start^TM system doesn't activate the fan until the desired temperature is reached, so it never blows cold air. Select models use Hyper-Heating INVERTER (H2i®) technology that operates effectively down to -13º F. These models give true year-round comfort from a single system

Part load performance

Part load performance of the heat pump must be properly taken into account, and be based on relevant testing standards.  
Night set back is a choice in some calculation models; this is not relevant for heat pumps and should not be a part in a new calculation model.  
 Back up heaters is sometimes necessary to complete the energy demand of the house. Back up heaters should be included in the calculation model. Supplementary heating should be possible to choose between different sources of supplementary heat, e.g. electricity, solar or biomass heating

Our Mitsubishi heat pump

Our Mitsubishi heat pump

We installed a state-of-the-art Mitsubishi M-Series FE18NA heat pump that is rated at 21,600 Btu/hour for heating and 18,000 Btu/hour (1-1/2 tons) for cooling. Marc Rosenbaum, P.E. ran heat load calculations showing peak heating demand (assuming –5°F outside temperature) about 23,000 Btu/hour, assuming the air leakage we measured several months ago, before the house envelope was completed. If the air leakage ends up being cut in half from that measured level, the design heat load would drop to a little over 19,000 Btu/hour.

We think the FE18NA model will work fine for nearly all conditions, but we are also installing a small wood stove—the smallest model made by Jotül—for use on exceptionally cold nights.

The indoor unit of our heat pump is about 43” long by 13” tall by 9-3/8” deep and installed high on a wall extending in from the west wall of the house—next to an open stairway to the second floor; it is controlled with a hand-held remote. The outdoor unit, installed just off a screen porch on the west side of the house is 35” tall by 33” wide by 13” deep. It is under an overhang and held off the ground by granite blocking.

Heat pumps

Heat pumps

Technicians from ARC Mechanical installing the outdoor unit.
Photo Credit: Alex Wilson

Heating with electricity makes sense if instead of using that electricity directly to produce heat—through electric-resistance strip heaters—we use a device called a heat pump. For every one unit of energy consumed (as electricity), two to three units of energy (as heat) are delivered. This makes heat pumps significantly less expensive to operate than oil or propane heating systems in terms of dollars per delivered unit of heat.

Heat pumps use electricity in a seemingly magic way, to move heat from one place to another and upgrade the temperature of that heat in the process. Heat pumps seem like magic because they can extract heat from a place that’s cold—like Vermont’s outdoor air in January, or underground—and deliver it to a place that’s a lot warmer.

Very significantly, heat pumps can be switched from heating mode to cooling mode with a flip of a switch. In the cooling mode, they work just like standard air conditioners

Installing a Mitsubishi

Installing a Mitsubishi air-source heat pump in our new house

The indoor unit of our Mitsubishi minisplit heat pump. Click to enlarge.
Photo Credit: Alex Wilson

Thirty-five years ago, when I first got involved with energy efficiency and renewable energy, the mere suggestion that one might heat with electricity would be scoffed at by those of us seeking alternatives to fossil fuels.

Amory Lovins, founder of the Rocky Mountain Institute, likened using electricity for heating to “cutting butter with a chainsaw.” Electricity is a high-grade form of energy; it doesn’t make sense to use it for a low-grade need like heating, he argued. It made much more sense, we all agreed, to produce that 75-degree warmth with solar collectors or passive-solar design.

So, it represents a bit shift that I’m now arguing that electricity can be the smartest way to heat a house. And that’s what we’re doing in the farmhouse we’re rebuilding in southern Vermont. I should note, here, that all of our electricity is being supplied by a solar array on our barn

Causes of Malfunctioning

Causes of Malfunctioning Reversing Valve:
1. Solenoid not energized. In order to determine if the
solenoid is energized, touch the nut that holds the
solenoid cover in place with a screwdriver. If the nut
magnetically holds the screwdriver in the Cooling mode,
the solenoid is energized.
2. No voltage to solenoid. Check the voltage and if
there is no voltage, check the wiring circuit.
3. Valve will not shift:
a. Undercharged: check for leaks.
b Valve Body Damaged: Replace valve.
c. Unit Properly Charged: If it is on the heating cycle,
raise discharge pressure by restricting airflow
through the indoor coil. If the valve does not shift,
tap it lightly on both ends with screwdriver handle

Common Causes

Common Causes of Unsatisfactory Operation of Heat
Pumps on the Heating Cycle
A. Dirty Filters or inadequate air volume through indoor coil.
When the heat pump is on the heating cycle, the indoor
coil is functioning as a condenser; therefore, the filters
must always be clean, and sufficient air volume must
pass through the indoor coil to prevent excessive
discharge pressure and high-pressure cutout.
B. Outside Air into Return Duct: Cold outside air should not
be introduced in the return duct of a heat pump installation
on the heating cycle close enough to the indoor coil to
reduce temperature of the air entering the coil below 65°F.
Air below this temperature will cause low discharge
pressure, thus low suction pressure and excessive defrost
cycling with resultant low heating output. It may also cause
false defrosting.
C. Undercharge: Undercharge on the heating cycle will
cause low discharge pressure resulting in low suction
pressure and frost accumulation on the lower part of the
outdoor coil.
D. Poor "Terminating" Defrost Thermostat contact. Defrost
thermostat must make good thermal contact on return bend,
otherwise it may not terminate the defrost cycle quickly
enough to prevent unit from cutting out on high discharge
pressure during the defrost cycle.

Funneling

Funneling AND DUCTWORK ACOUSTICAL LAGGING

Clamor transmitting from funneling and ventilation work can be a genuine issue in current

building development. Turbulent stream funneling commotion can be created by water or other

fluids passing through elbows, valves or other move pieces. Channel commotion is

brought about via air streaming past hindrances or limbs which brings about the vibration of

the metal ventilation work. This vibration then transmits commotion into the building

Kinetics Noise Control

Kinetics Noise Control has developed a unique and specific combination
absorber/barrier material which is well suited for pipe and duct wrapping applications.
KNM-100ALQ combines a 1.0 lb./sq. ft. barrier material with an aluminum foil facing
on one surface and a 1” or 2” (25 or 50 mm) thick quilted fiber glass decoupler layer
on the opposite surface. This product thus combines the decoupler and the barrier
into a single product which significantly minimizes the cost, time and labor required to
use both a separate barrier and a separate decoupler layer. The reinforced barrier
aluminum outer layer provides a clean surface that is easily adhered with tape. This
aluminum covering also increases the mechanical strength, wearability and fire
retardancy of the barrier. The barrier used in this product features an STC of 28,
which is more than sufficient for most normal HVAC plumbing and duct applications.
In the event that higher acoustical performance should be required to suite an
unusual application, a second layer of KNM-100ALQ can be overlaid on top of the
first layer, with care taken to stagger and overlap the joints.

The easiest

The easiest and best treatment technique for the control of funnel and conduit

breakout clamor is to wrap the channeling and ventilation work with acoustical cladding. This

acoustical material comprises of three (3) segments:

1. Vibration damping material (for sheet metal)

2. Light thickness decoupling material

3. Acoustical boundary overwrap

Relevant local building

Relevant local building and fire codes should always be referenced for the suitability
of all materials used within an occupied space within a building.
All piping and ductwork should be supported from the deck above via vibration
isolation hangers in lieu of rigid rods. Vibration isolation hangers suppress any
vibration which might be present within the piping from traveling up the rod into the
building structure. Further, at through-wall passage points the piping or ductwork
must be prevented from making any rigid connection with the building via the use of
conventional insulation sleeves between the piping and the wall.

Acoustical barrier

Acoustical barrier wrap improves the transmission loss of the pipe or duct and
therefore minimizes breakout noise. This barrier needs to be a heavy material
which is sufficiently flexible so as to permit wrapping around small diameter
piping. In the past lead sheeting was utilized for this purpose but recent concerns
over lead exposure and legal restrictions concerning its use have rendered this
material obsolete. Current barrium sulfate loaded vinyls are best suited for this
application as this material presents no known health hazards. It is important that
there be no barrier gaps or open areas over the region of the installation as these
represent significant acoustical “leaks” that greatly reduce effectiveness. Barrier
weights of 0.5 lb./sq. ft. to 1.0 lb./sq. ft. (2.5 to 5.0 kg/sq. meter) are commonly
specified as these materials are thin enough to permit good workmanship by the
installing contractor. Should additional acoustical performance beyond the
capabilities of a single barrier layer be required for a particularly sensitive project,
it is recommended that a second layer be applied over the first. For optimum
results, this second layer should be separated from the first barrier layer with a
decoupler as discussed in paragraph 2 above. This “double layer” of acoustical
cladding provides superior acoustical performance compared to the use of a
single, heavier layer.

Acoustical cladding

Acoustical cladding material should be used around all piping and ductwork which
passes through noise-sensitive areas within buildings. While it is recommended
that, for most applications, the wrapping should be continuous over the length of
the pipe or duct, it is appreciated that there are some instances where this
represents a large amount of material. Partial wrapping may be acceptable for
some non-critical applications. It is recommended that cladding be used a
minimum of 10 pipe diameters upstream and 20 diameters downstream of all
transitions, tees, valves, branch takeoffs or similar to ensure laminar flow beyond
the cladding.

Light density

Light density decoupling material provides an air space separation between the
pipe or duct and the exterior barrier cladding. This decoupler material is
commonly specified to be light density fiber glass with a minimum of 1” (25 mm)
thickness. Thicknesses greater than 1” offer improved capabilities up to a
practical upper limit of approximately 2” to 3” (50 to 75 mm). The decoupler
material needs to be light and porous as it is the air trapped within the material
which serves the purpose of acoustically separating the wall of the pipe or duct
from the exterior barrier cladding. As an analogy, it is the air space between two
(2) panes of glass which provides the insulation properties of a window. Care
should be taken in the event that a pipe carrying steam or hot water is to be
wrapped to ensure that the temperature insulation capabilities of the decoupler
satisfy the project requirements.

Canopies

Canopies
Design
The canopy hood needs to be designed and operated
to ensure effective removal of cooking fumes. It needs
to be a suitable size and have enough extraction to
minimise fume spillage into the kitchen. There should be
a canopy hood for every appliance and other sources
generating fumes and heat. The canopy hood should
be as close as possible to the source, taking into
account the work requirements.
The airflow into the canopy should be uniform and
constant, and meet the appropriate design flow for the
appliances and room ventilation rate. Canopies and
ductwork need to be constructed from non-combustible
material and made so they discourage accumulations
of dirt or grease, and condensation. There should be
suitable access to the ductwork, to allow regular cleaning
to prevent accumulation of fat etc. Grease filters need to
be readily removable for cleaning/replacement.

Replacement air

Replacement air
The ventilation system design should take into account
the need to replace extracted air. Mechanical and/or
natural means can provide make-up air, but it should
be fresh and unadulterated from the outside.
In smaller kitchens, there may be sufficient
replacement air drawn in naturally via ventilation grilles
in walls, doors or windows.
Where air is drawn in naturally, some means of control
over pest entry is usually needed. A fine mesh grille
will restrict the ventilation, and a larger grille area
can compensate. However, for larger installations, a
mechanical system using a fan and filter is more suitable.
The ‘clean air’ should not be taken from ‘dirty’ areas,
eg waste storage, smoking areas etc. The make-up air
should not impair the performance of flues serving gas
appliances.

Performance

Performance
The extraction rate is best calculated from the
information supplied with the appliances. It should also
take account of air change rates required for kitchens.
Where canopies are not used, eg where extraction is
through ventilated ceilings, consult a competent heating
and ventilation engineer to calculate the appropriate
ventilation rates.
The design should avoid draughts where the kitchen is
subdivided (eg wash-ups, vegetable preparations).
Maintenance
Mechanical ventilation systems should be maintained
in efficient working order in accordance with the
manufacturer’s/installer’s instructions.

what type of specific

what type of specific
equipment you will
need.
In generic terms a
typical equipment
package to inspect,
clean and
decontaminate HVAC
systems will include:
• Vacuum collection
system – puts
ductwork under
negative pressure
(suction).
• Agitation tools –
used to dislodge
accumulated dirt,
debris and
contaminates. This
includes power
brushing systems,

Portable electric

Portable electric
vacuum collection
systems offer the most
flexibility in that you
can clean virtually any
type (residential,
apartments, condos,
light commercial and
commercial) of
building with them.
You bring these
collectors into the
building and position
them where you can
be the most
productive. You zone
off (divide up) the
HVAC system to
achieve the suction
you need to clean.
These units operate
on 110 or 220 volt, 50
or 60 Hz., and have
HEPA filtration.

portable gas vacuum

portable gas vacuum
collection systems are
less expensive than
truck mounted units,
but like them, they sit
outside and you bring
in the large 50’ to 100’
long suction hose to
connect to the
ductwork. Depending
on the system you
may or may not have
to zone off the HVAC
system to achieve the
suction you need to
effectiviely clean.
You are limited to
cleaning residential
and one or two story
commercial buildings.

The large truck

The large truck
mounted units offer
lots of suction so you
typically do not have
to zone off the HVAC
system. These units
sit outside and a large
50’ to 100’ long
suction hose is
brought into the home
or building and
connected to the
ductwork. You are
limited to cleaning
residential and one or
two story commercial
buildings with the
truck mounted units.
These units are also
the most expensive
and require the most
maintenance.
• Trailer mounted and

Direct Replacement of Exhaust Air Limitation

Measure 1: Direct Replacement of Exhaust Air Limitation The economic justification for this measure was made by comparing equipment first cost and energy cost differences between an exhaust-only hood system versus an equivalently performing short-circuit hood system for a 10’ section of cooking line. An exhaust-only hood provides adequate capture and containment in this hood section with 1,500 cfm of exhaust air. The replacement air is assumed to come from the room in both cases. An equivalently performing 10’ short-circuit hood would have to exhaust 3,000 cfm with 1,500 cfm of replacement air being directly injected into the hood and the remaining 1,500 cfm coming from the room.  The basis of comparison used the costs of the hoods, the cost of the exhaust fans, and the cost of the addition makeup air unit required for the short-circuit system. The energy comparison used the brake horsepower difference between the exhaust and makeup air fans. The difference in brake horsepower was then converted to KW and multiplied by 15-year hourly energy cost data.  The systems were assumed to operate from 11 am to 11 pm everyday to simulate a typical restaurant serving lunch and dinner. Climate Zone 12 was used as the source of the energy costs but the energy savings are not associated with climate and would apply to all climate zones. Other metrics like the amount of ductwork, fire-proofing insulation could also be compared but since there is no component of a short- circuit hood system that is smaller and thereby costs less over an exhaust-only hood system, the comparison is limited to this small set of essential equipment to justify the costs.  Equipment cost data has been provided by a kitchen hood vendor.

Effective kitchen ventilation systems

Effective kitchen ventilation systems
The objectives of an effective kitchen ventilation
system are to:
■ remove cooking fumes at source, ie at the appliance;
■ remove excess hot air and bring in cool, clean
air, so the working environment is comfortable.
Inadequate ventilation can cause stress,
contributing to unsafe systems of work and high
staff turnover;
■ make sure that the air movement in the kitchen
does not cause discomfort, eg from strong
draughts;
■ provide enough air for complete combustion at
fired appliances, and prevent the risk of carbon
monoxide accumulating;
■ be easy to clean, avoiding build-up of fat residues
and blocked air inlets, which lead to loss of
efficiency and increased risk of fire;
■ be quiet and vibration free.

Type I Exhaust Hood Airflow Limitations

Measure 2: Type I Exhaust Hood Airflow Limitations The cost justification for this measure compares two kitchen hood designs of equal capture and containment performance. The Base Case uses an unlisted hood sized to meet prescribed code minimum or ASHRAE Standard 154 exhaust rates. The Proposed Case uses a listed hood sized to meet 30% better than ASHRAE Standard 154 Rates listed in Table 1.
3.3 Measure 3: Makeup and Transfer Air Requirements The economic justification for this measure was completed by comparing the energy and energy costs required to condition a kitchen over a range of transfer air percentages of kitchen exhaust air. These costs were graphed to illustrate the relative energy cost savings of using the maximum transfer air

Measure 4

Measure 4: Commercial Kitchen System Efficiency Options The cost effectiveness of demand control ventilation kitchen systems has been studied by the utility, Southern California Edison (SCE), who commissioned a study in 2009 which reviewed five commercial kitchen installations using DCV. The installations were all based on the Melink Intelli- hood system and included installation costs and exhaust fan energy savings only. Air conditioning energy savings were not studied. The installations represented different sectors of the market: smaller quick service restaurants and larger hotel and resort kitchens. The results of their study are used here to justify the cost effectiveness of DCV system as a design option for this measure.

Statewide Energy Savings

Statewide Energy Savings  The statewide energy savings associated with the proposed measures were calculated by multiplying the per unit estimate with the statewide estimate of new construction in 2014. The new construction forecast was derived from a study Southern California Edison’s Food Service Technology Center performed (SCE 2009

4.2 Measure 2:

4.2 Measure 2: Type I Exhaust Hood Airflow Limitations Equipment and electrical costs of each case were compared. Only the hoods, exhaust fans, and makeup fans were used. Similar comparisons could include differences in duct sizes, diffuser size and counts, and the conditioning energy. As these additional comparisons would reveal the same differences as the values used, they were not included. Table 4below compares the equipment costs between an exhaust and makeup air system using an unlisted hood versus a listed hood. The unlisted 10’ canopy wall hood for heavy duty used requires an exhaust rate of 550 cfm per linear foot of the leading edge of the hood. A similar listed hood requires an exhaust rate of 385 cfm per linear foot. The hood costs per the vendor we consulted are the same. The explanation for this is that the hoods have similar amounts of sheet metal and require similar amounts of labor to construct. The only difference between them is the vendor’s expense to test their hood designs for listing. It was explained that most cataloged commercial hoods are listed which creates cost competition so there is no economic benefit to pursue an unlisted hood. The exhaust fans and makeup air fans cost data reflect fans sized for the specific hood cfm. In the scenario developed, there is a $5,676 difference in the equipment. Table 5 below compares the power and electrical costs to exhaust and makeup the different air rates. The electrical costs assumed 5,400 hours of operation a year and an average electrical rate of $0.15 per kilowatt-hour. The annual electrical cost difference between the systems is $1,523. The data shows that listed hoods cost the same as unlisted hoods but the fans cost more for system with the higher exhaust rate. Subsequent, the energy costs are also more for the system with the higher exhaust rate.

A scenario

Measure 3: Makeup and Transfer Air Requirements A scenario describing a typical kitchen/dining room design was developed as the basis of comparison for the range of transfer air ratios in different climates. The scenario uses the following assumptions:  1,000 square foot commercial kitchen  10,000 cfm exhaust hood  Cooling supply airflow: 2,000 cfm or 80% of the exhaust cfm   Supply air temperature was  to 55°F  Space temperature setpoint, return air, and transfer air temperatures were set to 70°F  Cooling load of 9.5 w/sf  $0.12/Kwh Electrical Rate  $1/therm Gas Rate  0.0005 KW/cfm fan energy use  1 Kw/ton cooling equipment efficiency  0.70 thermal efficiency for gas heating equipment  Hour of operation: 6am to 10pm daily for a total of 5,838 hours per year.

A spreadsheet

A spreadsheet was created that used these assumptions to calculate the costs associated with fan energy, cooling energy, and heating energy over a year using 5°F bin weather data. The weather data was filtered to only the number of hours in each temperature bin within the 6am to 10pm hours of operation. The annual energy costs were tabulated over the range of available transfer air percentages. Low transfer air percentages represent higher amounts outside makeup air that must be conditioned. High transfer air represents lower amounts of outside makeup air.

Condensation, Dripping, and Frost

Condensation, Dripping, and Frost

Problems arise during cold temperatures when warm, moist air from the home reaches the attic, is not vented to the outside, and it lingers in the cooler and drier attic. As the dew point is reached, water vapor held in the warmer air condenses on cold attic surfaces — building components, such as rafters, trusses, and roof sheathing. See figure 2. In the winter, during low temperatures, the condensed moisture can appear as frost.

Measure 1: Direct Replacement of Exhaust Air Limitation

Measure 1: Direct Replacement of Exhaust Air Limitation The equipment cost for the measure case based on an exhaust-only hood system described in the test scenario is $1,604 less than an equivalently performing short-circuit hood system in the base case when comparing the hoods, exhaust fans, and makeup air units. The energy cost difference between the two systems over 15 years using the 2011 energy data for CTZ 12 is $6,435. As demonstrated, there is no performance or economic benefit associated with short-circuit hood systems when compared to exhaust-only hood systems.  The proposal allows 10% direct replacement to allow hood manufacturers to employ different capture and containment strategies that resemble short-circuit hoods but do not have the performance deficiencies of short-circuit hoods.  Systems that use less than 10% direct replacement include the Halton Capture Jet, which has been tested by the PG&E Food Service Technology Center and shown to provide equal or better C&C compared to an exhaust-only hood with the exhaust flow rate.

If too much water

If too much water soaks into the insulation, it can become compressed and lose its insulating power. We have even seen ice crystals that formed throughout fiberglass insulation. When the insulation is in this condition, it loses some of its insulating power. This leads to greater heat loss, colder rooms, a greater demand on the furnace, and to higher utility bills.

Frost collection on the underside of a roof.

Frost collection on the underside of a roof.
Frost collection on the underside of a roof.
This moisture causes damage in two ways. First, moisture condensing on the roof’s structural building components will soak into the wood. This can lead to wood rot and the deterioration of roofing materials. Second, moisture eventually will drip onto the building components below.

Unvented moistur

Unvented moisture in cold weather results in compromised roof structure, lower energy efficiency and damaged building components below the attic.

During cold weather, proper ventilation helps prevent moisture from condensing on the roof, the structural members, the insulation, and the framing and sheetrock below the attic.

Rust, Warping of Roof Decking,

Rust, Warping of Roof Decking, and Deterioration of Roof System

In a nature, rust can structure on metal segments like nails and clasp, which can in the end debilitate and fizzle. Distorted top decking can happen after unreasonable dampness leaks into the top decking and breaks up the cements that hold them together. The decking twists or droops between the rafters. Disintegration of the top framework, including the underlayment and shingles can be created by inordinate hotness and dampness not being vented out of the loft.

Buildup or Mold

Buildup or Mold

Shape and Mildew developing on the underside of a top.

Shape and Mildew developing on the underside of a top.

A damp environment is the ideal spot for mold or mold to develop. Mold development in lofts causes a wellbeing danger for the individuals living in the home, and can result in crumbling of the inside building segments.

Fitting ventilation lessens dampness develop and minimizes the opportunity for mold to develop, which delays the life of your home's building segments and decreases wellbeing effects

Air pollution sources

Air pollution sources

Another step the Agency recommends is identifying potential sources of air pollution within the home. Taking a survey of your home and identifying where heating systems are located, how chemicals are stored and how well-ventilated individual rooms are can provide an avenue for improved air quality, even if those areas aren’t the actual cause for poor air quality.

If you’ve taken the above steps and still want to undertake testing for individual air pollutants, contact your local health department for guidance on how to begin evaluating your home’s air quality with the help of professionals.

Dripping

Dripping moisture also can penetrate into the attic floor and, eventually, into the ceiling below. If this occurs, the top-floor ceilings may exhibit water stains and paint damage. When this type of damage is visible, that is a good chance that the framing material behind the sheetrock has also been damaged by moisture.

Cancer risks from radon

Cancer risks from radon

However, due to its strong correlation to lung cancer, it’s strongly recommended that homeowners test their homes for radon, especially when moving into a new home or occupying a home where no radon mitigation system exists. Homeowners concerned about carbon monoxide can purchase carbon monoxide detectors that signal when unhealthy amounts of the gas build up.

The EPA says that health problems can be one of first indicators of an air quality problem, especially if the appearance of symptoms coincides with a recent move to a new residence, a recent remodeling project or a recent application of pesticides. It recommends consulting with your health provider or local health department to help determine if poor air quality may be the cause of health symptoms.

Should you test your air?

Should you test your air?

If you’re concerned about the quality of your indoor air, you should examine a number of issues before turning to costly indoor air quality testing. Because there is not one comprehensive indoor air quality test, hiring a firm or purchasing a multiple test kits prior to eliminating possible sources of poor indoor air quality can be a costly and time-consuming exercise.

Controlling secondhand smoke

Controlling secondhand smoke

The most effective way to prevent secondhand smoke from contributing to poor indoor air quality is to never smoke indoors.  If any of your home occupants smoke indoors, ask them to do so outside. The same goes for visitors who may smoke.

Smoke

Smoke

One of the easiest indoor air quality factors to control is the negative effects of smoking tobacco products indoors. Not only does smoking indoors produce a foul odor that can linger in upholstery, clothing and carpeting, secondhand smoke can cause cancer, serious respiratory illnesses and aggravate asthma. Children are especially vulnerable to secondhand smoke.

Volatile organic compounds (VOCs) from household items

Volatile organic compounds (VOCs) from household items

According to the EPA, volatile organic compounds or VOCs are chemicals that can be commonly found in household products such as cleaning products, paints, chemical strippers, waxes and pesticides. Other in-home products that can produce VOCs that contribute to poor indoor air quality include floor coverings, furniture, electronic equipment, air fresheners and dry-cleaned clothing.

VOCs from household items can be especially hard to pinpoint as the cause of poor indoor air quality because the VOCs naturally evaporate into the air when the products are used or stored.

Controlling pollutants from combustion devices

Controlling pollutants from combustion devices

The most effective way to control indoor air pollution from combustion or heating devices is to make sure they’re used and maintained properly. The EPA recommends that you make sure there’s adequate ventilation in any area where a fuel-burning or heating device is being operated. If and when you use a heating or fuel-based device, make sure that it’s properly installed and up-to-date on maintenance and repairs.

Function

How do you get heat from cold air?

Air/water heat pumps utilise the heat energy of the outside air.

The heat pumps are designed for outside placement and transform an existing radiator system into an excellent, complete heating system. 

Heat pump technology is actually based on a very simple, well-known principle. It works in a similar way to any domestic refrigerator, using a vapour compression cycle. The main components in the heat pump are the compressor, the expansion valve and two heat exchangers (an evaporator and a condenser). A fan draws the outdoor air into the heat pump where it meets the evaporator. This is connected in a closed system containing a refrigerant that can turn into gas at very low temperatures. When the outdoor air hits the evaporator the refrigerant will turn into gas. Then, using a compressor, the gas reaches a high enough temperature to be transferred in the condensor to the house’s heating system. At the same time the refrigerant reverts to liquid form, ready to turn into gas once more and to collect new heat. Using an inverter-driven heat pump compressor, the system can be regulated so that heat output matches the exact capacity required at any given time. This means the heat pump will only consume the exact energy needed, making it highly efficient. In the summer, the refrigeration circuit is capable of operating in reverse to provide cooling on demand. Air/water heat pumps utilise the heat energy of the outside air. The heat pumps are designed for outside placement and transform an existing radiator system into an excellent, complete heating system.

Why throw out old energy when you can recycle it instead?

Why throw out old energy when you can recycle it instead?

An heat recovery ventilation unit is basically an energy recycling system. It collects energy from the warm inside air as it leaves your home via the ventilation system, and re-uses it to heat up fresh incoming air.

If you’re building a new house or developing new apartments, now’s the perfect time to take advantage of NIBE’s energy efficient heating technology. Install a heat recovery ventilation unit and you can enjoy a healthy, oxygen-rich atmosphere inside your home, at the same time as reducing your electricity consumption.

Controlled domestic ventilation

Controlled domestic ventilation

Controlled domestic ventilation can be used in both low-energy and older houses. In low-energy houses the controlled ventilation system guarantees the required air exchange rate, even with the doors and windows closed. When older houses are renovated better thermal insulation could be used, along with fitting new windows to enable controlled domestic ventilation to achieve the necessary air exchange rate. These types of older building are often affected by street noise. A ventilation system would therefore be beneficial in these cases too. Controlled domestic ventilation with heat recovery When ventilation based on opening windows and controlled domestic ventilation without heat recovery are used, the energy from the inside air is not used. However the ventilation heat requirement accounts for a considerable part (40 – 50%) of the total heat requirement. In contrast to this, controlled domestic ventilation with heat recovery reuses the energy from the exhaust air. Not only that, the additional heat generated internally from lighting, people and domestic appliances is also utilised through heat recovery. Our FIGHTER exhaust air heat pumps facilitate heat recovery and supply the energy recovered from exhaust air for the domestic hot water and even the heating. Not only does energy recovery ensure a healthy and comfortable form of heating, it also produces considerable savings in terms of heat energy, along with CO2 emissions.

Can it be docked to solar heating?

How often do I need to change filter? And where can I get a new one?

Information about air filters can be found in your “Installation and Maintenance Instructions” for the product. New filters can be ordered from NIBE if the filter needs changing.

---

Can it be docked to solar heating?

Here you can find a dockningsschema which describes the above case.

---

In which room should the ventilation air be taken?

It is slightly up to the individual, but it is recommended to take the air from bathroom, kitchen (not kitchen fan), hall, utility room etc. The supply air to the house is often through grilles under the windows or in the walls and these are placed in other rooms where one does not extract any air. Through this one obtains a natural flow and exchange of air throughout the house.

Frequently asked questions

---

What is a heat pump and how does it work?

A heat pump is an electrical device that extracts heat from one place and transfers it to another. The heat pump is not a new technology; it has been used in Sweden and around the world for decades. Refrigerators and air conditioners are both common examples of heat pumps.

Heat pumps transfer heat by circulating a substance called a refrigerant through a cycle of alternating evaporation and condensation (see Figure 1). A compressor pumps the refrigerant between two heat exchangers. In one heat exchanger, the evaporator, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings. The refrigerant is then compressed en route to the heat exchanger, the condenser, where it condenses at high pressure. At this point, it releases the heat it absorbed earlier in the cycle.

Controlled domestic ventilation

Controlled domestic ventilation

Introduction

Nowadays we spend around 90% of the time indoors. This undoubtedly places great demands on the climate inside. The inside climate is affected considerably by odours, harmful substances, noise and temperature. In every building there is a certain amount of basic ventilation, even if it is only produced by air coming through windows, doors, pipe ducts and walls. This type of ventilation, in older houses in particular, provides the necessary exchange of air. Ventilation is also provided through opening windows and doors, perhaps also when one or more windows are opened at an angle. Strong wind pressure and a difference in temperature between the interior and the exterior also increase the exchange of air. On the other hand, a weak wind or small temperature difference will reduce the required air exchange rate. This uncontrolled ventilation also accounts for a significant part of the heating costs and causes a considerable proportion of non-renewable energy resources to be wasted. Low-energy house In contrast to this, there is the low-energy house concept. A construction design is used in this type of house that prevents heat from escaping through use of effective thermal insulation. This also means that low-energy houses benefit the environment. But even with this construction design, there is still the problem that the required hourly air exchange rate of 0.5 – 1.0 is not achieved. To achieve the required air exchange rate either the windows would have to be opened, which would run counter to the whole low-energy house concept, or installation of a controlled domestic ventilation system with heat recovery would have to be considered.

pollutants

These pollutants vary considerably according to the inside climate conditions, the state of ventilation and the design and use of the inside area. When energy-saving measures were introduced in the early 1970s, considerable efforts were made to improve the insulation used in the construction industry. This led to a reduction in the air exchange rate inside buildings. From a health and allergy perspective, the ideal air exchange rate would be 0.5 – 1.0, but in actual fact, air ex change rates in appropriately insulated houses are only between 0.3 and 0.5, which means that the polluted inside air is exchanged far too in-frequently. Based on the reasons given above, an increase in the incidence of complaints affecting the population is inevitable. This is where controlled domestic ventilation can have a particular role to play. Its purpose is to control temperature and dampness, while ensuring that the quality of the inside air is totally hygienic. The relevant technical guidelines and hygiene regulations are stipulated by DIN 1946.

Save energy, water and money

Save energy, water and money An energy-efficient, A-labelled heating circulator uses up to 80% less energy than a conventional D-labelled model, cutting around 10% off an average household's annual electricity bill. To benefit from year-round savings on energy bills and CO2 emissions you should replace your old circulator with an ALPHA2 now. Also new building projects deserve ALPHA2.

Likewise, the Grundfos hot water recirculation pumps help you save water and energy. Many people wait for hot water for more than 60 seconds. With instant hot water, litres of cold water is saved from running down the drain during the wait.

Overview

Overview

Unmatched home comfort
Most people associate a comfortable home with a warm and cosy indoor environment. That is why a domestic heating circulator pump is an integral part of any household with central or district heating. It represents the heart of the system and is responsible for moving hot water from the heating boiler to heating devices such as radiators, and for securing optimum heating regulation.

Most people also appreciate the pleasure of instant hot water. A hot water recirculation solution ensures that you never have to wait for hot water in showers and taps.

Expansion valve

Expansion valve

On its return to the evaporator from the condenser the high-temperature, high-pressure liquid refrigerant must be changed to the low-temperature, low-pressure liquid that enters the evaporator. This is usually achieved by a throttling device known as the expansion valve. When the hot liquid passes through this valve, not only will its pressure be reduced but at the same time its temperature will drop. As the pressure drops, refrigerant starts to evaporate in the valve and the heat of evaporation is taken from the refrigerant itself which causes its temperature to drop and the result is a low-temperature, low-pressure mix of liquid and vapour.

Compressor

Compressor

In the compressor the low pressure of the low-temperature refrigerant from the evaporator is raised to a pressure that is sufficiently high to match the desired condensing temperature in the condenser. During compression not only the pressure but also the temperature of the refrigerant will increase. 

DUCT CLEANING EQUIPMENT

DUCT CLEANING EQUIPMENT

VACUUMS

Contrary to popular belief, it is not necessary to own a giant truck mounted vacuum to perform professional quality duct cleaning. In fact, in larger buildings it is imperative to use portable equipment in order to gain access to all cleaning locations. Truck mounted duct vacuums are more suitable to residential work. Two types of vacuums are required for successful duct cleaning. First is a large HEPA filter equipped negative air machine generating at least 4000 CFM. This unit is connected directly to the duct and maintains the section being cleaned under negative pressure to prevent contamination of the occupied space. It also collects all debris loosened in the cleaning process. A portable HEPA vacuum should also be on hand for contact vacuuming of turning vanes, plenums, coils, drip pans, registers, and other surfaces