söndag 30 november 2014

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.

lördag 29 november 2014

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

fredag 28 november 2014

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

torsdag 27 november 2014

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
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”).

onsdag 26 november 2014

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
Spin Door - round access door and door frame
installed by spinning the door frame into a round
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.

tisdag 25 november 2014

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.

måndag 24 november 2014


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
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:

söndag 23 november 2014

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).

lördag 22 november 2014

Air Scrubber

Air Scrubber: An air filtration device (AFD) using HEPA
filtration configured to re-circulate air within a defined
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
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

fredag 21 november 2014

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.

torsdag 20 november 2014


Antimicrobial: Describes an agent that kills or inactivates
microorganisms or suppresses their growth (See ASTM
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

onsdag 19 november 2014

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.

tisdag 18 november 2014

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

måndag 17 november 2014

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.

söndag 16 november 2014

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
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

lördag 15 november 2014

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.

fredag 14 november 2014

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

torsdag 13 november 2014

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 StartTM 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

onsdag 12 november 2014

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

tisdag 11 november 2014

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.

måndag 10 november 2014

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

söndag 9 november 2014

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

lördag 8 november 2014

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

fredag 7 november 2014

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.

torsdag 6 november 2014



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

onsdag 5 november 2014

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.

tisdag 4 november 2014

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

måndag 3 november 2014

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.

söndag 2 november 2014

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.

lördag 1 november 2014

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.