Frequently Asked Questions
What are the advantages of a gas heat pump over an electric one?
It is not necessary to reinforce the circuit breaker and the electro installation because of the installation of the electric appliance; the gas HP delivers a higher heat output, the heated water from the engine can be used to prepare hot water, it saves electricity and therefore emissions from its centralized generation.
When is it better to use a cogeneration and when to use a GHP?
A gas heat pump can advantageously be used where a CHP unit cannot be connected to a distribution grid, where there are no supports for cogeneration electricity or where an operation of a gas HP is planned to limit its own consumption of electricity for cooling.
What is the payback period of the investment in a gas heat pump?
The payback period typically ranges from 4 to 6 years. Ideally, if the yearly operation is around 8,000 hours, it can even be within 2 years.
Are there any subsidies to acquire a gas heat pump?
Yes, there is an Operational Programme Enterprise and Innovation for Competitiveness, under which there is the Energy Savings support programme. This programme also covers the purchase of a gas heat pump.
To whom does a GHP pay off?
Under the current conditions, it is worthwhile to install a gas heat pump, e.g. in gas boiler rooms of central heating where it can run in coaction with large CHP units or gas boilers. The industry is another vast field of its application. However, similarly to the cogeneration, each potential installation needs to be well evaluated and calculated. There is no universal manual.
If the GHP is so good, why is it not used more often?
The technology is still relatively young, little known and it has been searching its way to the market. For small sources up to 50kW of heat output, the absorption heat pump will surely be used, for the outputs over 100 kW, the gas heat pumps with combustion engines will be used due to their better fuel utilization.
Do you have any references?
Yes, for example TEDOM production plant in Trebic, dairy in Varnsdorf, waterpark in Perpignan, France or a meat processing plant in Brno. Currently, several other projects are being prepared.
Can the ratio between the heat and cold generated by a GHP be changed?
The ratio of the cooling and heating output is given by physical principles and the gas heat pump design. It is approximately 4 : 3 in favour of the heat while the deviations from this ratio can be a maximum of up to 15%. Therefore, it is not possible to think that if I need more cold, I can simply decrease the heat generation.
What emission produces a GHP?
A gas heat pump produces the same emissions of NOx and COx as gas combustion boilers. As a standard, they do not exceed 150 mg NOx/Nm3 of exhaust gases.
What are the differences between a GHP air-water and water-water?
The following terms name the media with which a heat pump operates. Air-water means that the heat is taken by the coolant evaporation in the air evaporator. At first sight, it looks the same as any other cooler. Water-water means that the energy is taken from the water which is more pleasant for a heat pump as no outdoor unit needs to be installed.
What is COP and how is it calculated?
COP is an abbreviation of the English term Coefficient Of Performance, which is clearly defined as the ratio of the energy generated and delivered, so:
COP = cooling or heat output [kW] / device energy input [kW]
COP = cooling or heat output [kW] / device energy input [kW]
What is the difference in COP for an electric and a gas heat pump?
For an electric heat pump, the energy input is the electricity. The current heat pumps can increase it up to four times. The entry then looks like this:
COPe = heat output [kW] / device energy input [kW] = 4 / 1
It means that I pay 1 kWh of electrical energy to drive the heat pump and I get the heat output of 4 kWh. For a gas heat pump, we put into the denominator the energy contained in the supplied fuel, mostly in natural gas. The COP of gas heat pumps is around 1,8 (for a comparison: modern gas boilers reach 0,95).
COPg = heat output [kW] / input in consumed fuel [kW] = 1,8 / 1
The seemingly lower COP is the result of a ratio of other numbers than for the electric HP. Despite the lower COP, the utilization of primary fuel energy is significantly higher for gas heat pumps than for electrical ones as the fuel is utilized completely in them. For the electric heat pumps, the heat loss of the power plants exceeding 60% is not considered and only the part of the fuel that has been transformed into electricity is put into the denominator.
COPe = heat output [kW] / device energy input [kW] = 4 / 1
It means that I pay 1 kWh of electrical energy to drive the heat pump and I get the heat output of 4 kWh. For a gas heat pump, we put into the denominator the energy contained in the supplied fuel, mostly in natural gas. The COP of gas heat pumps is around 1,8 (for a comparison: modern gas boilers reach 0,95).
COPg = heat output [kW] / input in consumed fuel [kW] = 1,8 / 1
The seemingly lower COP is the result of a ratio of other numbers than for the electric HP. Despite the lower COP, the utilization of primary fuel energy is significantly higher for gas heat pumps than for electrical ones as the fuel is utilized completely in them. For the electric heat pumps, the heat loss of the power plants exceeding 60% is not considered and only the part of the fuel that has been transformed into electricity is put into the denominator.
