Refrigerator Heat pump efficiency

There are four different criteria used to describe the heat pump efficiency. In all of these criteria, the higher the number, the better the performance of the system. The efficiency of the heat pump is determined by comparing the amount of energy supplied by the heat pump amount of energy it consumes. It is important to emphasize that the effectiveness of the measurements are based on laboratory tests and do not necessarily measure the heat pump performs in real operation conditions.

Coefficient of performance (COP)

The COP is the most common measure used to assess the effectiveness of the heat pump. COP-coefficient of heat pumps heat power of electric energy input, as shown below:

CC = Heat Output/Input Electric Energy

For example, an air-source heat pumps Cops tend to have from 2 to 4; they delivery from 2 to 4 times more energy than they consume. Water and geothermal heat pumps, as a rule, have the Cops 3 to 5. The COP air-source heat pumps decreases, and the temperature drops. Thus, the two COP ratings are usually given for the system: one on 8.3Р’C (47BF) and other 9.4Р’C (17VF). When comparing the Cops, make sure that the ratings are based on the same temperature of external air. Cops on land and water source heat pumps do not vary as much because ground water and temperature constant temperature.

Comparing the Cops is useful, it does not give a complete picture. When the temperature drops below 4.4Р’C (40VF), outdoor coils heat pump should be thawed periodically. It is actually possible for outdoor coil temperature be below zero when the heat pump heating. In these conditions, any moisture in the air frost on the surface of the cold coil. In the end frost could get enough to keep air from passing through the coil and the coil would then lose efficiency. When the coil efficiency is reduced enough to appreciably affect the throughput of the system, frost, should be eliminated. To defrost coils, heat pump their cycle and heat moves from home to the outdoor coil, to break the ice. This reduces the average COP significantly.

In fact, some of the heat pump has a power saving function that allows the device to defrost only when necessary. Others will go to defrost cycle at regular intervals when the device is in heating mode. Another factor which reduces the overall efficiency of the air-heat pumps is their inability to provide enough warm even in the coldest days of winter. This means that the backup heating system is required. It is often the electrical resistance of the heat, which has COP only one. Whenever the temperature drops to-3.8Р’C-1.1Р’C range, or whatever his point of equilibrium, and that the electric resistance heat feet, overall efficiency of the system drops.

Primary Energy Ratio (per)

Heat pumps can be activated either electrically or engines, internal combustion engines or gas engines). If electricity comes from an alternate source (e.g. hydro, wind, solar and other), heat pumps also use of primary energy sources upstream, as thermo-electric factory-as natural gas, motor. When comparing the heat pump system is managed using different sources of energy, it is more appropriate to use the TV as defined in Holland et al. (1982)as the ratio of useful heat supplied to the primary energy input. So this may be due to the COP by the following formula:

TV = n KS

where n is the efficiency with which the primary energy consumption is converted to work up to a shaft of the compressor.

However, due to the high COP, TV, below, is high compared to conventional fossil fuel systems.

In the case of an electrically driven compressor, where electricity is generated from coal power stations, efficiency r can be below 0.25 or 25%. The above equation shows that the gas engine driven heat pumps are very attractive with primary energy ratio point of view, since the values of r 0.75, or better, can be obtained. However, heat recovery systems, as a rule, are judged by their potential saving money, not their potential energy savings.

(EER)energy savings potential.

EER is used to evaluate the heat pump efficiency of the cooling cycle. The same rating system is used for air conditioners, making it easy to compare different units. In practice, EER ratings higher than 10 are the most desirable. EER is the ratio of the cooling capacity is provided to the electricity consumed in the following way:

EER = cooling capacity/Input Electric Energy

The heating Season efficiency factor (HSPF as well)

Heat pump varies significantly, depending on the weather and how much additional heat is required. Thus, a more realistic measure, especially for air heat pumps, calculated on a seasonal basis. These measurements are called the heating Season efficiency factor (HSPF as well) for heating. In industryB standard test for overall efficiency of heating provides rating known as HSPF as well. Such laboratory tests attempts to take into account the decrease in efficiency caused by thawing, fluctuations of temperature and additional heat, fans and on/off Cycling. HSPF as well is the estimated seasonal heating shares with seasonal consumption, as follows:

HSPF as well = Total Heating Output of the Total Electrical Energy Input

It can be seen as " average COP " for the entire heating system. In HSPF as well 6,8 roughly corresponds to the average COP-2. HSPFs 5-7 considered good. The higher HSPF as well. more efficient the heat pump. To estimate the average COP, split HSPF as well 3.4.

Most communal sponsored heat pump programs require heat pumps have HSPF as well, at least 6.8. Many heat pumps meet this requirement. Some heat pumps have HSPF as well ratings above 9. In General, more efficient heat pumps are more expensive. Compare saving energy, VAT included.

Seasonal Energy Efficiency Ratio (SEER)

As explained above, the heat pump varies significantly, depending on the weather and the number of extra heat needed. Thus, a more realistic measure, especially for air heat pumps, calculated on a seasonal basis. These measurements are called Seasonal Energy Efficiency Ratio (SEER) for cooling cycle. Therefore SEER rating seasonal cooling performance of the heat pump. SEER is the ratio of total cooling heat pump to the total electrical energy input during the same period.

SEER = Total Seasonal Cooling/Conclusion of the Total Electrical Energy Input

Naturally, the SEER units will vary, depending on where he is. Seers 8-10 considered good. The higher the SEER more efficient heat pump cool. SEER is the coefficient of thermal energy is removed from the house than the energy used for heat pump operation, including the fans. A SEER, as a rule, is much higher than HSPF as well with defrosting is not necessary and there is no need for expensive additional thermal energy for air conditioning weather.