Heat Pump Primer  
 

 

"A heat pump can potentially generate 3 times more heat delivered than it consumes in Electrical power"

A typical small high tech, 1500watt (Electrical power consumption) Inverter  Heat Pump can deliver over 3500watts of heat!

What is a heat pump?

A device that converts energy from Electrical to kinetic to Thermal energy through the use of compressed refrigerant. 

How does it work? 

It works like a reversible refrigerator. It sucks heat out of one location, and pumps it to another.

Why are they so efficient?

A heat pump does not create heat like a resistance heater, it extracts heat from one location and transfers it to where you want it.

Why does EEH encourage the take up of Heat pumps? 

In EEH's name is the word Efficient; a properly installed heat pump is the most efficient & cost efficient way of maintaining an automated home temperature when the outside temperature is above -10c. 

It heats in Winter, cools in summer

They are generally quiet, and can be installed as a central unit with electrostatic air cleaners

No extra gas lines charges, or perceived risks inherent in gas use.

What is an Inverter Heat Pump?

Most refrigeration appliances turn off and on to control temperature. This is very inefficient. 

An Inverter Heat pump, throttles back the compressor, reducing its load, it thermal output and its power requirements. It can run just ticking over a lot of the time to maintain temperature, thus they are much quieter & much more efficient. 

We recommend Inverter Heat Pumps, we do not recommend brands. 

 

What should I look for in a  Heat Pump?
  • Brand name, local service, warranty
  • Inverter variable speed with scroll compressor
  • Freon R410a or better
  • Noise of operation, 
    • Int 47/day/44night
    • Ext 52db
  • Compare you max cold temperatures with the max cold operating temps of the Heat pump. You can get them down to -20c.
  • Style:
    • Wall mount
    • Multi wall mount (one compressor)
    • In wall
    • Cassette ceiling mount
    • Central unit mount with plenums to various rooms
 
Mitsubishi ran test where a regular heat pump was replaced by an R410a + Inverter heat pump with no other differences, in an office environment and the newer unit used 70% less power than the old unit.

Other interesting facts:

Ground, water (ie rivers, or ocean) and ambient air typically contain an enormous amount of latent heat, however, its low thermal level does not normally enable it to be directly exploited for the heating gains. If we want to utilize low temperature (so called 'low-potential') heat, it must first be converted to that of a higher temperature. This what a heat pump can do.

Remember: It does not create heat, it CONVERTS heat.

Operation in the home is generally exceptionally quiet, and thermostat controlled. As a bonus, a heat pump can be reversed in the summer to air-condition the home.

PRINCIPLE OF OPERATION


Heat pumps operate on the principle of a closed cooling circuit similar to that used in the household refrigerator. One side is cold the other hot. For instance a refrigerator removes heat from its inside as well as from the food, and transfers it via the condenser on the outside, which is hot, thereby direct to the kitchen.  

State of the art inverter heat pumps, use variable loading to reduce cycle times and lower power consumption.

Even though the freezer on your fridge may be at -10c, the amount of heat transferred to the air in the room seems negligible.  In an EEH home, this cumulative heat, plus the operational temperature of the compressor, helps heat the home indirectly. 

What is special is, depending upon the design and ambient temperatures, you can get up to 3 times more heat per given power consumption over conventional inefficient resistance heater using the latest inverter heat technology..

The SYSTEMS

The heat pump has 3 main units, an evaporator, a condenser, and a compressor. The compressor typically uses with "Soft" environmentally friendlier Freon such as Freon 22 and Freon R134a. 

   

A cutaway view of a typical outside part of the heat pump, showing the internal compressor and condenser/evaporator unit. 

This is an air-to air exchanger, however outside heat exchangers can be had for emersion in the ocean, streams, deep bores or thermal vents. Heat pumps generally have Extremely quiet operation in side.

Unlike an air-conditioner, a heat pump is reversible. This means the evaporator and condenser do double duty, heating in the winter and cooling in the summer. When in heating mode the condenser is inside, while the compressor and evaporator are outside. In air-conditioning mode the condenser becomes the evaporator and the evaporator become the condenser.

The types of heat pumps on the market are varied with the most typical being air to air. The most commonly encountered other combinations involve the air-to-water, air-to-air, water-to-water, antifreeze-to-water or earth-to-water types. If you live near a (non-freezing) river, ocean, or have a flowing well, the outside unit is highly effect year round, allowing the whole system to operate at peak effectiveness. In geothermal areas, heat pumps can be an excellent way to ecologically exploit the potential.

An outside unit just using air for its exchange,  is best operated in temperatures above  -10c. 

 
 

You can now buy hot water cylinders with built in heat pumps to economically heat water. The capital cost remains fairly expensive.

 
 

Residential Heat Pumps

A residential heat pump takes low-temperature heat from an outdoor medium (such as air, ground, groundwater or surface water) and mechanically concentrates it to produce high temperature heat suitable for heating the interior of homes. Because most of the heat is moved (pumped) from the outdoor source to the indoor source, the amount of electricity required to deliver it is theoretically much less than using electric resistance heat directly.

Modern heat pump systems are very reliable and have become exceedingly common in Sunbelt areas. By far the most common types are air-to-air heat pumps which use outdoor air as the heat exchange medium. 

Want more technical information?:  

The theoretical efficiency of heat pumps is greater than 2000%. Thus, the COP, or Coefficient of Performance, would indicate 20 times as much heat delivered as used. However, the practical efficiency of the best air-to-air heat pumps produce COPs of 2.33 to 3.0. Because COP varies with the outdoor temperature, a heating season performance factor (HSPF) is determined which takes into account operation under varying outdoor temperatures as well as part load impacts (effects of running short cycles under mild conditions, coil defrost, etc.). HSPF is rendered as Btu/Watt so that typical values are on the order of 7.2 - 8.4 KJ/W. Older systems may have HSPFs of 6.3 - 7.4 KJ/W.

 
 

CapEx  & OpEx & Gas vs Electric

When calculating the capital cost of installing a heat pump vs gas be sure to include the installation costs of both including connection to the gas main. (You will have power installed anyway) If you are getting gas installed anyway, this may be mitigated.


Operating costs: Be sure to add in the monthly access charge for gas, typically $30 or more.  It has been our experience that electricity prices rise with gas prices, and with no extra gas access fees, your Heat Pump should cost less to operate. With the pending loss of gas from local sources, gas prices can be realistically expected to rise above the electrical power cost over the next few years.

Other factors to take into consideration: Gas requires an active flue, also factor in leakage risks. Heat pump compressors are normally located outside, and can generate some noise in their vicinity, so take location of Windows into your consideration for location. 

 
 

Notes:

  • Most pictures are of actual homes, customized for each customer, and therefore may show features not included in the base offering, but available on request as an option
  • Purchase Large  168 page, high quality, full colour, Catalogue available containing all current models. $65 including postage. Payment by cheque or Credit card (via PayPal): Please contact us for details
  • Models are also available on CD for $7 including P&P, and include high resolution pictures: Please contact us for details
  • All models can be ordered with Garages
  • All Models can be customised
  • All models can be optimised by the use of basements, a low cost way to enlarge any home

Please contact us for more information

All contents of this Web site are (c) 2004 by Energy Efficient Homes Limited, and others