Temperature pumps can be a great extremely energy-efficient kind of space heating and cooling : provided they are measured, installed, and used appropriately.
On this page:
Advantages plus disadvantages of heat pumping systems
How heat pumps work
Heat pump energy sources
Energy efficiency of temperature pumps for space heating
Heat pump capacity
Temperature pump sizing
Also notice heat pump configuration and installation.
Air-to-air heat pumping systems, the most frequent type in New Zealand, use refrigerant to soak up heat from one space and transfer it to another via a heat exchanger (often a fin or perhaps coil). The electricity source to a heat water pump is just used to move the heat around, not really to generate it : the heating itself offers a passive energy source.
Temperature pumps are popular in New Zealand due to their own high efficiency and ‘clean’ energy image. Most usually are installed to provide heat, although it is starting to become even more common for them to be able to also be useful for summer time cooling. Some local authorities offer you incentives to switch to be able to heat pumps from fewer efficient, more polluting technologies.
Advantages and disadvantages regarding heat pumps
Features of a good air-to-air heat pump contain:
it is very effective at converting energy to be able to heat (optimum efficiency is if the difference between supply and provide temperatures is very small)
it provides a medium to fast supply of heat
that has the ability to be able to provide heating and air conditioning
Many have timer settings programmable for seven days in addition to some connect to home WiFi to allow remote control control via smartphone.
Just how heat pumps job
Warmth pumps operate on much the same principle to a refrigerator. Refrigerant flows through attached indoor and outdoor coils. In heating mode, since the liquid refrigerant moves to the outdoor coils, it passes via an development valve that creates quick expansion of the water, causing it to come to be a gas. This effects in very rapid cooling of the refrigerant. And then as it flows through the outdoor coil, that is able to take in heat energy from the particular air. Before it runs through the indoor coil, it passes through a air compressor where the gas is usually compressed, increasing both the pressure and the temp. As it moves via the indoor coils, typically the gas condenses, releasing important heat.
Most heat penis pumps in New Zealand are usually air-to-air units. The warmth source is plentiful, nevertheless may be variable, which could affect efficiency. As temps fall, air-to-air heat pumping systems can require defrosting plus then are not supplying heat. This makes them ineffectve in areas with extremely cold winters (particularly when the humidity is also high).
There are two additional sources of energy used for central heating pump:
Ground-to-air temperature pumps have the benefit of fairly regular sub-soil temps year-round, typically averaging 12–15°C at around 1–1. a few metre depth. They as a result have fairly high efficiencies even on very cool winter nights. They are usually considerably more expensive to install, however. Most parts associated with New Zealand do not have the climate extreme conditions or heating demands in order to justify the cost.
Water-to-air heat pumps – water is also a great source of low grade heat but is only suitable wherever buildings are situated near a water supply.
Energy performance of heat pumps with regard to space heating
As warmth pumps only move temperature and do not really generate it, they possess a very high percentage of heat output to power input. This heating power efficiency is expressed as a coefficient of overall performance (COP), while cooling power efficiency is expressed since an energy efficiency percentage (EER).
Typical domestic heat pumps have a COP of 2–4. 5, this means the heat pump generates about 2–4. 5 periods as much heat as the electricity it makes use of (under optimum conditions). Several heat pumps have COP’s of up to 5. 7. The efficiency of an air-to-air heat pump decreases because the temperature difference between source and supply raises – as outside temperature ranges drop, the heat pump’s energy efficiency reduces.
Temperature pumps are currently the particular only type of heating, apart from solar, where the COP is (usually) greater than 1, which can make them the most effective form of purchased space heating commonly available.
The chilling energy efficiency ratio (EER) is typically about a couple of. 5–4. 0, which indicates the heat pump generates about 2. 5–4 times as much cooling energy as the electricity it uses. Some heat pumps have EER’s as higher as 5. 8.
Any time selecting a heat pump, consider its primary employ. Whether it will mostly be used for heating, choose for a high POLICE OFFICER; if mostly used for cooling, select for a new high EER.
Under the Power Efficiency (Energy Using Products) Regulations 2002, heat pumps for sale in New Zealand must meet the Minimum Energy Performance Regular (MEPS) given in AS/NZS 3823. 2: 2013 Performance of electrical appliances – Atmosphere conditioners and heat pumps – Part 2: Power labelling and minimum vitality performance standards (MEPS) requirements.
An Energy Rating Tag must be displayed about excellent heat pumps with regard to sale. It shows a new star rating – the more stars (out associated with a possible 10), a lot more energy efficient the warmth pump is. More successful models have lower working costs.
Heat pump capacity
The heating capacity regarding an air-to-air heat water pump (in the heating cycle) is typically between 2–16 kW for domestic systems. The cooling capacity (in the cooling cycle) will be generally about 10–20% fewer than heating capacity.
To be able to reflect a variation inside capacity according to outside temperature ranges, heat pumps might have about three heat capacity ratings. These kinds of are based on standard testing under laboratory circumstances.
H1 rates the unit’s heating output when the outside temperature is 7°C.
H2 rates the heating system output at 2°C background temperature.
H3 rates the heating output at -7°C ambient temperature.
These scores enable you to find the appropriate temperature pump for your climate and household requirements (i. at the. the design temperature in addition to heating load) of personal situations.
It is crucial to note the marketed COP values are centered on lab tests ~ used, the overall effectiveness of a heat water pump is likely to be lower, e. g. one rated as COP of 2. 0–4. 5 may have an actual overall working efficiency of around POLICEMAN 1. 5–3. 0.
Warmth pump size
Getting dimension right for heat pumping systems is essential for maintaining their own efficiency.
If the temperature pump is actually big for the space requiring heat (or cooling):
fixed rate systems will cycle upon and off repeatedly (as the point temperature will end up being reached very quickly), which often is inefficient and minimizes the life expectancy in the unit
ducted systems could have higher than necessary pressure, which can cause duct leakage.
If the heat pump is usually too small , the product will run continually since it attempts to achieve the set point, which often reduces the outside coil temperature and cause this to defrost regularly.
A recommendation is to stay away from using extremes of twelve-monthly temperatures when selecting typically the ambient design condition plus also to avoid exaggerating the set points regarding indoor heating and air conditioning.
Heat pump sizing measurements must consider:
region, place and orientation of typically the building
specific local conditions
orientation of windows
seasonal high and low normal temperature ranges
levels of padding
number and types associated with occupants and their degrees of activity
solar gain.
The rough rule of browse to determine the heat requirements for rooms is made for:
Older uninsulated houses ~ use 65 W/m3 area volume
Newer well-insulated residences – use 50–55 W/m3 room volume.
Ducted heat pump systems require mindful design. They can have got heating energy loss regarding more than 30% when the ducts are overlong and/or have many bends, or travel through uninsulated space for example attics. The particular majority of heat water pump systems do not contain a fresh-air supply method – they only recirculate room air. Ventilation specifications need to be maintained by other means.