Industrial Heat Pumps

 

Industrial heat pumps: F.A.Q.


What is a heat pump?

What is the difference between a heat pump and a refrigeration system?

What are advantages and disadvantages of waste heat recovery with the use of a heat pump?

What are the costs of a heat pump installation?

What are energy savings due to the application of a heat pump?

What is the principle of operation of a heat pump?

Which different operation principles are possible?

Up to which temperature levels can a heat pump be applied?

Are there funding possibilities when installing a heat pump?

What is a heat pump?

WP met uitleg 2A low temperature waste flow can be upgraded to a usable high temperature source of energy with the use of a heat pump. Among the different types of heat pumps that have been developed, the mechanical heat pump is the most widely used. Its operating principle is based on compression and expansion of a so called 'refrigerant'. A heat pump has four main components: evaporator, compressor, condenser and expansion device. The refrigerant is the working fluid that passes through all these components, extracting heat from the waste heat source and delivering it to other streams. Electric energy is required to drive the compressor and this energy is added to the heat stored in the refrigerant.

 

What is the difference between a heat pump and a refrigeration system?

Heat pumps and refrigeration systems are basically the same installations. Both a heat pump as well as a refrigeration system transport heat from a low temperature level to a high temperature level. The only, and important difference is their difference in purpose. A refrigeration system aims to cool, while a heat pump aims to heat its 'target'. Situations in which an installation is used to both cool and heat, both names can be used.
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What are advantages and disadvantages of waste heat recovery with the use of a heat pump?

Advantages:

  • The heat pump has a very high efficiency as compared to gas heated systems;
  • Application of a heat pump directly results in large energy savings;
  • Significant reductions on CO2 emissions;
  • In particular situation as, for example, discharge of waste water, cooling before discharge is desirable.

Disadvantages:

  • An investment is needed;
  • Due to the electricity usage of a heat pump a sufficient electrical connection needs to be present;
  • Some refrigerants used in a heat pump are toxic or flammable.

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What are the costs of a heat pump installation?

Investment costs of a heat pump depend strongly on the location and application. Important factors are:

  • Required heat capacity: the more capacity is needed, the more expensive the installation will be.
  • Required temperature: a higher temperature requires more expensive components.
  • Number of installations: depending on specifications, the decision can be made to either build a number of small installations or one large installation.
  • Available space to connect a heat pump to an existing installation.

The HeatPump Check will give a good estimation of the installation costs.
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What are energy savings due to the application of a heat pump?

The amount of energy saved depends on the temperature difference that need to be overcome. The temperature difference directly influences the COP of the heat pump.

Imagine a process using 500 kW of heat that is provided by steam injection. Steam has been made in a 85 % efficient steam boiler with natural gas and the process has 6.000 annual hours of operation. Gas consumption can then be estimated to be 400.000 Nm3 each year. When a heat pump is connected to the process, no steam injection is needed anymore. This heat pump has a COP of 5,0 and thus uses 100 kW of electricity to deliver 500 kW of heat. Electricity consumption can now be estimated to be 600.000 kWh annually.

Because of the connection of a heat pump, much as 57% can be saved on primary energy and 43% on CO2 emission. Financial benefits depend on gas and electricity costs. For example, energy prices of € 0,08 / kWh and € 0,25 / Nm3 give an annual benefit of € 52.000,-. Back to top

What is the principle of operation of a heat pump?

The principle of operation of a heat pump is based on the physical property that "the boiling point of a fluid increases with pressure". By lowering pressure, a medium can be evaporated at a low temperature while an increase of pressure will lead to condensation at a high temperature level. This physical property thus enables the transport of heat from a low temperature waste stream, towards a high temperature heat consumer. More can be read about this topic on the page: How it works.
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Which different operation principles are possible?

A low temperature waste flow can be upgraded to a usable high temperature source of energy with the use of a heat pump. Among the different types of heat pumps that have been developed, the mechanical heat pump is the most widely used. In the mechanical heat pump the condensation temperature of a refrigerant is increased with the use of a compressor. Other types of heat pumps are, for example, the absorption heat pump, the adsorption heat pump and the hybrid heat pump. More information about the different principles of operation can be found on this website, page: How it works.
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Up to which temperature levels can a heat pump be applied?

The application area of a heat pump depends on the type of heat pump and the refrigerant applied. With a mechanical heat pump and Ammonia as its refrigerant, maximum temperatures of 90 to 100 °C can be reached. For higher temperatures, pressure levels of 63 bar or higher are needed. Components will become very expensive at these high pressures causing pay back times to become too long. With the application of n-butane as a refrigerant in a mechanical heat pump, higher temperatures up to 130 °C can be reached. For butane however there is a fire and explosion hazard due to which extra safety measures are necessary. With the use of absorption heat pumps temperatures of 90 to 120 °C can be reached.

The efficiency of a heat pump depends on the temperature level of the waste heat source. When high temperatures are desirable, the waste heat source should have a relatively high temperature as well to guarantee a proper payback time.
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Are there funding possibilities when installing a heat pump?

In the Netherlands electrically driven heat pumps as well as adsorption and absorption heat pump are eligible for the Dutch EIA funding. With this subsidy a net benefit of app. 10% can be acquired on investment costs. To apply for this subsidy certain efficiency requirements have to be fulfilled. More information on EIA can be found on the website of RVO.nl.
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