These are three important questions that are often asked by people who have been building their homes for decades. The answers to these questions are not given well enough, so that a man with a humanistic training rather than a technical one can understand them.
1. What is a HEAT PUMP
HEAT PUMP is a mechanism that pumps heat from one environment to another. The refrigerator is a HEAT PUMP. The refrigerator removes heat from food inside and removes it to the outside through the radiator mounted behind it. Food losing heat cools, and the heat that is expelled through the radiator heats the room.
Air conditioning is another common example of HEAT PUMP. The air conditioner removes heat from an enclosure and expels it. For example, there may be 40 outsideoC, and in the cooled room to be 32oC but HEAT PUMP - air conditioning will remove the extra heat in the room with 32oC (heat released by people in the room, heat released by electrical appliances in operation, etc.) keeping the temperature constant and will expel it to the outside environment, where the temperature is 40oC.
2. How the HEAT PUMP works
After the first answer to the question What is a heat pump, things are simpler. We do not explain physical functioning here, we will formulate a useful answer to someone interested rather in the practical and useful part of a HEAT PUMP.
Very simplified, HEAT PUMPS have compressors, refrigerant (usually freon) and pump heat from a lower (colder) environment to a warmer environment. The name is a metaphor, a comparison with water pumps, which pump water from the bottom up.
3. Why is the HEAT PUMP mounted?
In order to have a good answer, the one who asks this question must do an exercise of imagination: to imagine that at the house he builds, instead of the usual thermal power plant, which runs on gas or wood, he would install a PUMP HEAT, a refrigerator 20 times larger than the refrigerator used for food. It would have the mission to cool the earth under the house, and the heat extracted from the earth to be discharged into the house. The few hundred tons of earth will cool a little, and the heat from there will heat the house.
The question remains, however, why should anyone install a HEAT PUMP on the house they are building?
The answer is simple and is called simple: COP.
The COP is the efficiency factor of the HEAT PUMP installed to heat the house, it shows how much heat (in Kw) is obtained by consuming one Kw of electricity.
A well-mounted HEAT PUMP has a COP over 4, in particularly favorable situations it can even exceed 6.
THE HEAT PUMP installed as a heating system for a home consumes electricity, but produces (introduces into the house) at least 4 times more heat.
There are some necessary details at this time, in order to have all the data and for the beneficiary of a house to make the right decision to install or not a HEAT PUMP.
As you can see, the HEAT PUMP alone is not an investment, it must be considered with all the elements that make it functional to have a good COP. This inflexible rule would sound like this: WITHOUT A MINIMUM BLOW 3, IT IS NOT WORTH MOUNTING A HEAT PUMP.
From this rule there are some doubts, namely it is necessary to clarify which are the factors that influence the COP of a HEAT PUMP. There are three main factors and I present them briefly:
- Effective quality of the HEAT PUMP. There is not much to say here, the buyer of a HEAT PUMP must have a wise attitude.
- The quality of the installation in the building. HEAT PUMPS have good efficiency, good COP, that is, if the heat pump difference is small. In translation it means that the temperature difference between the environment from which the heat is extracted and the thermal agent with which the house is heated must be as small as possible. Therefore, for a good use of the HEAT PUMP, it is necessary to provide in the house installations that work with low temperature thermal agent, namely HEATING IN THE FLOOR or installations with CONVECTOR VENTIL. The use of radiators nullifies all the advantages of the HEAT PUMP.
- The quality of the environment from which the heat is extracted. It is actually the most important of the three. According to the environment from which the heat is extracted, there are three categories of HEAT PUMPS as follows:
a) AIR HEAT PUMP - heat pumps that extract heat from atmospheric air. They have the great advantage that they are cheap to install, but they are only useful when the outside temperature is above -4oC. They are also called CHILERS. For an installation with the production of mixed thermal agent, the heating load at low temperatures being taken over by another system, can be a good choice but it must be seen if the investment is not too high compared to alternatives.
b) WATER HEAT PUMP - has as operating principle the extraction of water from a groundwater table, usually with a constant temperature of 12oC - 13oC, cool it to 2oC - 3oC and insert it back into the groundwater. The problems that this system raises are mainly due to the fact that circulating large amounts of water requires consumable water filtration and treatment systems. This variant, in some cases, can lead to COP over 5.