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High temperature heat pump (industrial heat pumps)

High temperature heat pump (industrial heat pumps)

Traditionally heat pumps are used for refrigeration purposes and to deliver process cooling.

In recent years the ability of heat pumps to deliver process heat as become more of interest for several industries under the aspect of energy efficiency, utilization of excess heat and reduction of climate gas emissions related to generated of process heat. High temperature heat pumps, or industrial heat pumps, can be defines as heat pumps being able to deliver heat.Current heat pump solutions are mostly limited to heat supply of around 70°C to 80°C, while industry process are quite often designed for heat supply temperature of around 100°C to 200°C. 

 

High temperature heat pumps can be used for everything from hot water production to upgrading waste energy to be used in other processes. One of the main challenges of high temperature heat pumps is the integrability into  the production process industry and to match the available heat source to the required heat demand. 

 

Supply of process heat by heat pumps

 

Steam producing heat pumps Mechanical Vapor Recompression (MVR)

High temperature heat pumps can be used to produce high pressure steam, which is the preferred choice as heat carrier in the industry. Industrial steam is used in everything from drying of food, textiles and paper, sterilizing of milk and equipment, and as heat carrier in most industrial processes. Steam produced from heat pumps is eco-friendlier compared to steam from conventional boilers due to higher energy efficiency, often 50% less energy per kilo steam is required. Natural refrigerants such as steam and butane are suitable in high temperature heat pumps.

 

Mechanical Vapor Recompression does not generate steam as regular high temperature heat pumps but recompress steam from processes such as drying or evaporation (concentration). In steam drying, wet products enter the drying chamber, together with hot steam. The high temperature steam warms up and evaporates the water within the product. The cooled steam exits the dryer, while a smaller excess stream is compressed to a higher pressure. Now, the high-pressure steam is condensed in a heat exchanger, and the rest of the steam is warmed up and can be used again as drying agent. Implementing MVR in dryers and evaporators often reduce the energy requirement by over 50%.

 

We work within these areas:

  • System integration and evaluation of different of solutions 
  • Development of compressors and design of heat exchangers 
  • Energy efficiency by implementing high temperature heat pumps
  • Combined heating and cooling
  • Turbo compressors 
  • Steam producing heat pumps 

Typical projects for us are:

  • Mapping of energy reducing solutions in different processes
  • Simulation, dimensioning, planning and implementation of different solutions 
  • Develop new solutions within high temperature heat pumps/MVR

The methods we use are:

  • Testing of components and systems in SINTEF Energy lab(LINK) and SINTEF HigheffLab (LINK)
  • Determination of key point indicators in the solutions
  • On-site measurements of important parameters 
  • Simulation and modelling 

Why choose SINTEF?

SINTEF is a world leading research institute with expertise within high temperature heat pumps, especially by using natural refrigerants. SINTEF has developed a cascade heat pump which can deliver both heating at cooling and has one of the highest temperature lifts in the world. For steam compression, SINTEF has broad experience from national and international projects in cooperation with both the industry and other research facilities. 

 

Who are we doing this for? 

Companies who are aiming to reduce their carbon footprint and reduce energy related costs while maintaining HSE and product quality. 

 

Relevant projects:

HTHP-rigg på SINTEF Energy Lab
HTHP-rigg på SINTEF Energy Lab

 

Facts Heat Pumps

 

What is a heat pump?

A heat pump is a technical installation which transfers heat from a colder area to a hotter area by using mechanical energy.

 

The most know application is surely household refrigeration, in which the inside of the refrigerator is kept cold while the back of the refrigerator is getting warm.

 

In order to transfer this heat a working fluid called refrigerant is needed. The refrigerant is evaporated in the cold part of the heat pump, hereby removing energy from a system (=chilling). The refrigerant is then compressed and transported by a compressor (=mechanical energy) to the warm side where the energy during condensation of the refrigerant is given to another system (=heating). The cold and warm systems are separated and therefore heat is “pumped” from cold to warm. The temperature level of the cold and warm area is a result of different evaporation and condensation pressures in the system.

 

In most heat pump systems, the mechanical energy needed for the compressor is supply by an electric motor. It is the characteristic of a heat pump that the electricity consumption is lower than the transferred energy. This is expressed by the Coefficient of Performance (COP) which states how much useful heating or cooling is provided compared to the work supplied. The COP of a heat pump is commonly getting lower as higher the temperature difference between cold and warm area is.

 

Need for natural refrigerants:

Natural refrigerants (like CO2, ammonia, hydrocarbons) were the first generation of refrigerants and used until 1930, when the second generation of refrigerants was introduced under the aspect of “safety and reliability” [1].

 

However, their negative influence on the ozone layer forced the industry to introduce the third generation of refrigerants (HFCs e.g. R134a) through the Kyoto protocol.  HFCs then showed a high global warming potential (GWP) and will be phased out due to the Kigali protocol and the F-Gas regulation.

 

For industrial application from 2020 the installation of new refrigeration equipment and heat pumps containing refrigerants with high GWP (e.g. R134a, R404A, R407C, R410a, R507A) will be forbidden. The service of existing units can only be conducted by applying recirculated refrigerants causing price increase for maintenance. The units need to be phase out until 2030.

 

The industry now promised that the fourth generations of refrigerants (HFOs) will solve also this problem, however already now there are indications that also these refrigerants could cause problems, e.g. in the drinking water[2]. Consequently, there is an ongoing search for the “right” refrigerant and the trend goes back to the first generation of natural refrigerants which will cause no environmental impact.

 

In other words; if a natural refrigerant can be applied in in a heat pump this should be the favourable solution, since they can be handed safe, are cheap, environmentally friendly and will not be subject to future regulations.

 

[1]

Research & Development Roadmap for Next-Generation Low Global Warming Potential Refrigerants

 

[2] German Environment Agency 

Senior Research Scientist