What is a HEAT PUMP and How Does It Work? Where is a HEAT PUMP Used? What are its Advantages and Disadvantages?
- Oğuzhan ÇALIŞIR
- Oct 20, 2024
- 5 min read
Updated: Mar 15
Author: Dr. Eng. Oğuzhan ÇALIŞIR
WHAT IS A HEAT PUMP? WHAT ARE THE TYPES OF HEAT PUMPS?
A heat pump is simply a system that transports heat energy from one environment to another and is powered by electricity. As is known, energy cannot be created or destroyed, it only changes form or is transported from one place to another. A heat pump gets its name from its ability to “pump” or “transport” heat energy from one environment to another. An example would be submersible pumps. Just as submersible pumps do not produce water, heat pumps do not produce heat, they only transport it. Similar to submersible pumps being immersed in a water source to pump water, heat pumps cannot transport heat unless they are in contact with an energy source on earth. When the necessary conditions are met, large amounts of energy can be put to use at low cost.
Heat pumps are new to most people in the heating sector. However, the refrigerators, air conditioners, dehumidifiers and freezers in our homes are the product of the same logic. When the working environment complies with the logic of carrying heat, they can be grouped under the title of "heat pump". With the depletion of fossil fuels and the serious explosions in the prices of these fuels every day, as well as the development of environmental awareness, it is an inevitable result that many healing heat pumps will become known and widespread in the very near future.
Heat pumps are named according to their heat source. Heat sources found in nature are divided into 3 classes: soil, water and air heat pumps. Although their working principles are the same, air source heat pumps are the most commonly used in terms of access to the heat source (Figure-1).
HOW DOES A HEAT PUMP WORK? HOW DID IT APPEAR?
If refrigerators are used for heating or heating and cooling purposes, they are called heat pumps. Let's take the refrigerators used in our homes as an example. The interior environment where the food is located in the refrigerator is cold and the pipes behind it are warm because they release the heat to the environment. Almost everyone is aware of this phenomenon and wonders where this heat comes from. As can be seen in the example, refrigerators produce heat and cold at the same time. As can be understood, when we talk about heat pumps, we are referring to refrigerators. So heat pumps have been a known concept for a long time, in other words, they are not a new technology for the 90s.
Heat pump technology will logically play a very important role in the use provided with heating as the rising graph shown in cooling until the decay of the heat pump that first occurred in the 18th century. Heat pumps generally provide the transfer of heat production to its place. For this, a heat sink is needed to take the heat. Almost all of the heat pumps used explode the air as a heat sink. Today, heat pumps that use air as a heat sink are called Split Air Conditioners and chillers. The efficiencies of air-source devices show different values in the changes of outside air temperatures. As a result of the fact that the efficiency values do not remain even during the day, unexpected fixed increases occur in operating costs. The features that prevent these efficiency changes are acceptable heat sinks are also fixed. The intended used temperature is constant and acceptable heat sinks are soil and water.
Heat pumps can produce more energy than they consume using a traditional refrigeration cycle by absorbing stored heat and raising it to a level suitable for heating.
A large amount of low-quality energy absorbed from the environment is transferred to heat inside the heat pump (evaporator). This causes the temperature of the water to rise (even below zero) and causes the gases to be trapped from the liquid.
The refrigerant is then compressed by an electrically driven compressor, reducing the volume but significantly increasing the system. A heat exchanger (condenser) then heats the water for central heating, underfloor heating or domestic hot water by taking heat from the heat. After giving off the heat energy, the heat turns back into liquid and can absorb energy again after being stored through an expansion valve (Figure-2).
WHERE IS A HEAT PUMP USED?
Heat Pumps offer suitable solutions for all living spaces and offer large changes to liveable parts of spaces. Conventional heating systems can be used in almost every area.
· Houses
· Apartments
· Restaurants and Cafes
· Places of worship
· Hospitals
· Airports
· Shopping Malls
· Factories
· Commercial Workplaces
· Cattle / Livestock Farms
· Sports Complexes
· Pool Complexes
· Greenhouses
WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF HEAT PUMP SYSTEMS?
Heat pumps generally use 75% of the heat source energy, so they have low operating costs and are environmentally friendly systems. Air source heat pumps have the widest range of use since the heat source, namely air, is easily accessible all over the world. Ground-Water Source Heat Pump technology is based on the fact that the temperature at a certain depth in the earth remains relatively constant throughout the year. At the mentioned depth, the soil layer is warmer than the air in winter and colder in summer. Ground-Water Source Heat Pumps use this advantage given to us by nature by transferring the heat stored under the earth or in underground water to the building in winter and the heat inside the building to the underground in summer. In short, the underground acts as a heat source in winter and a heat sink in summer. Today, Ground-Water Source Heat Pumps are used for heating, cooling and hot water production. Since heat pumps can meet all of these needs with a single machine, they have become the preferred choice.
Heat pump systems have slightly higher investment costs compared to conventional natural gas systems. Operating costs are 10% less than conventional systems, depending on the variability of climate conditions. The payback period for heat pump systems intended for heating purposes only is 9 years. However, this period is reduced to 5 years for systems used for both heating and cooling purposes.
Heat pumps are much more reliable investment in distribution with photovoltaic (PV) systems. In the current annual rules, our situation desires to install a PV system as much as the amount consumed. In detached villa style houses, a PV system with a capacity of approximately 10-15 kWp can be installed on the roof area. This capacity is sufficient for both building lighting and heat pump. In this way, a system that is completely independent of conventional consumption such as natural gas and more environmentally friendly is obtained.
There is a similar situation in industrial buildings. According to the old rules, those who install PV systems on the roofs of these buildings that are larger than necessary can only sell the system as much as it is consumed. They either have to consume the excess or keep the system ready. In this way, they have turned to heat heating systems to increase their heating and cooling consumption.
Finally, as of January 2025, it has been made mandatory for all new buildings of 2000 m2 and above to use renewable energy (PV, Solar Energy, Heat Pump etc.) up to 10% of the building energy consumption. Considering that the capacities of hot water solar energy and PV systems are limited to the roof area and that it is very difficult to collect these systems on hipped roofs, there remains a more practical and applicable heat pump system. In the following years, this 10% increase will provide further capacity increases for heat pumps.
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