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R&D – Component Technologies

Component technologies is mainly the work done by Technical Institutes and by Original Equipment Manufacturers. focusing on:

  • Increasing the efficiency of the refrigeration cycle in relation to the choice of refrigerant;
  • Reduction of production costs;
  • Improvement of manufacturing processes.

This type of research is often confidential and if made public, the results can be found on scientific websites or at governmental websites, when part of a governmental financing scheme. An important source is IIR.

Important components are developed by a number of OEM’s in Japan. These developments by manufacturers are described extensively in the report on R&D from Japan and have presented at a number of workshops.

  • Compressor, these can be largely classified into scroll, rotary, and swing types;
  • Condenser, which can be placed outside or inside of the storage tank. Wrap around condensers also occur.
  • Evaporator, the challenges are numerous, ranging from noise reduction to optimisation of defrosting in cold climates;
  • Ejector, the difference between the high and low pressures can lead to large losses in the expansion valve, which can be reduced by an ejector;
  • Hot Water Storage Tank, where there is a special focus on better insulation methods and optimization of the stratification and draw off patterns;
  • Control Technology, focusing on smart control and combination/integration with other technologies.
DENSO CO2 Compressor
Insulation structure of storage tank
New structure for refrigerant distribution
Mitsubishi spiral gas Cooler

Component technology development in the United States is the basis for a number of R&D projects coordinated by Oak Ridge National Laboratories focusing on developing complete market fit products funded by DOE.

Gas Fired Adsorption HPWH at Oak Ridge National Laboratory

In the United Kingdom R&D work is done by Ulster University Centre for Sustainable Technologies with a focus on mapping and exploring the Variable Speed Compressor Performance for retrofit, which has tested in a pilot project.

Warwick University is active in the development of adsorption technologies for domestic applications, working together with Oak Ridge National Laboratory. Both institutes focus on optimization of components together with manufacturers.

Newcastle University has a focus on storage and PCM’s in relation to heat pumping technologies and heat pipes for compact Domestic Thermal Storage under the Thermac project.

Laboratory at Ulster University

In Switzerland two major component developments were reported upon, being:

  • Schiffmann proposed two radial compressors with mini impellers of less than 20 mm in diameter on a single shaft, running at variable speeds up to 240’000 rpm were designed as an oil free miniature radial compressor in a two-stage heat pump cycle. Further projects are ongoing with the integration into heat pump cycles.
  • Friedl proposed a new concept for the compression of the working fluid starting from a two-phase state at the compressor inlet to a saturated gas state at the compressor outlet with a temperature equal to the condensation temperature.
Miniature radial compressor (Schiffmann)

In Netherlands under the ‘Topsector Energie’-program a number of projects focus on topics related to HPWH’s , which are not specifically components.

The project on the Thermo Acoustic Heat Pump is a spin-off from the project run by ECN on industrial heat pumps. Project goal is to develop a prototype compact TAWP for decentralized heating and cooling of buildings with a COP of 3.5 to 4.0 (air / water) and a thermal capacity of 1kW. This contributes to compact, inexpensive and efficient developments in the field of heat pump technology in the built environment. With a thermal capacity of 1 – 100kW’s the heat pumps of Blue Heart are developed for residents and offices.

Blue Hart Energy B.V will produce the thermoacoustic as OEM supplying the component to heat pump manufacturers.

A compact heat battery, developed by Cellsius is the first completely loss-free heat storage, 10 times cheaper than electrical storage and much more compact than water or PCMs. This heat battery meets the innovation task of MMIP4.3 under the Dutch TKI Program, and is approaching market maturity in an integrated system combined with a heat pump.

Prototype of Thermoacoustic component

In Canada institutes and universities, like Queen’s University-Solar Calorimetry Laboratory and Carleton University, work on heat pumps in cold climates and combination with solar. Examples of projects are:

  • Research and development of Solar and HP water heaters (Experimental and TRNSYS modeling)
    • Based on plate heat exchangers/evap. & cond’s. used in side-arm thermosiphon and pumped configurations
    • Modeling and evaluation of stratified storages
    • Developed “Passive Backflush technology” to prevent scaling in hard water conditions
  • Plate gas-cooler for use in Trancritical-CO2Eco-cute HPWH –evaluated fouling rates
  • HPHW Evaluation-performance/cost comparison of wrap-around and immersed coil condenser versus brazed-plate side-arm

In other countries not participating in the Annex fundamental component research has been executed at:

Kungliga Tekniska högskolan developed compact heat exchangers to reduce the refrigerant charge making it possible to build a ground source heat pump with 10 kW heating capacity with 100 g refrigerant charge of propane. The Danish Technological Institute did research on a new HPWH with propane as refrigerant and a spiral heat exchanger in the tank with also the focus on reducing the charge.

Already studied in 1973 by Carel Sanders et al for air coolers, the topic of frost formation is still relevant for cold climate heat pumps. A number of papers at the Frost formation has been published at the 13th IEA Heat Pump Conference by AIT, University of Maryland, Korea Institute of Machinery and Materials and Waseda University.

Heat Exchanger developments at KTH