Air to water heat pump with natural refrigerants
In this project, a new generation af air to water heat pump will be developed, using propane (R290) as refrigerant. The aim is to increase the energy efficiency with 5-10 %. The new produet will be in the best energy class (A+++) and will keep the obligations in the EU Ecodesign regulation. The project will be conducted in cooperation with the biggest Danish manufacturer af heat pumps (Nilan NS) and three ether partners.
For many years, the Danish industry has been in process af changing towards natura! refrigerants. This has happened in the refrigeration industry, but not for heat pumps, except large heat pumps (>200 kW).
In this project, a new air to water heat pump will be developed in a cooperation between the biggest Danish manufacturer of heat pumps (Nilan A/S), the big whole dealer in equipment for refrigeration and heat pumps (H. Jessen Jurgensen), the manufacturer of fans (EBM Papst) and Vonsild Consulting who is an expert in using flammable refrigerants in a safe way. The Danish Technological lnstitute leads the project.
Air to water heat pumps are very important produets for Nilan A/S and are mostly used in well insulated houses providing floor heating. The heat pump is placed outdoor, and this is a good platform for starting using hydrocarbons as working fluid in heat pumps.
Using flammable refrigerant is a challenge, and this requires introducing some security efforts, which is not needed by using HFC refrigerants. But this can be done.
A new air to water heat pump will be developed and tested. After finalizing the project, Nilan will continue the work by putting the new produet in production.
This has succeeded in a cooperation between the partners which are Nilan (producer of heat pumps), H. Jessen Jürgensen (supplier of components and refrigerants), EBM Papst (supplier of fans), Vonsild Consulting (expert in safety), and Danish Technological Institute (DTI) (project manager, tests etc.).
The task is done by using Nilan’s existing Air9 heat pump as a basis. This heat pump was tested at DTI having an efficiency (SCOP) of 5,11. By using a simulation program and data for a new compressor (Hitachi) and a new evaporator (SEST), it was shown that the aim could be fulfilled.
A first prototype was built and installed with internal heat exchanger between liquid pipe and suction gas and electronic expansion valve. This prototype was also installed with a number of measuring points at the refrigeration cycle for analysis of the thermodynamic process.
The first prototype was measured to have an efficiency of SCOP = 5.21, which is a small improvement compared to the original model.
From the analysis of the test results of prototype 1, it was decided to skip the internal heat exchanger and to use an optimized evaporator with a slightly higher capacity.
A second prototype was built and this was tested and redesigned a couple of times until the results were satisfying. In the end, a thermostatic expansion valve was used. The second prototype was tested in accredited laboratory at DTI, and the result is SCOP = 5,32, P(design, - 10 C) = 4,0 kW and P(norm, +7 C)) = 6,23 kW. This is satisfying, and the efficiency is 4.1 % better that the HFC-model.
This new model is more efficient than all air to water heat pumps at the Heat pump list of the Danish Energy Agency. The heat pump is expected to be competitive on the market for energy efficient family houses because of the energy efficiency, the natural refrigerant and because of the simplicity of the thermodynamic cycle.
The product is safe to install and use since all refrigerant is placed outdoor.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| NILAN A/S | ||
| H. JESSEN JÜRGENSEN A/S | ||
| Vonsild | ||
| Ebmpapst Denmark ApS |
