Reversable heat pumps with natural refrigerants
The need for air conditioning has been on continuous rise in the past decades in Sweden and expected to rise even more in the future due to increasing outdoor temperature because of global warming. Therefore, heat pumps for space heating are also expected to run in reverse mode and provide air conditioning.
Background
Tens of millions of heat pumps are expected to be installed in Europe in few years where
the demand is great for environmentally friendly and energy efficient solutions. Natural
refrigerants, such as Ammonia, hydrocarbons, and carbon dioxide are seen as a potential
environmentally friendly alternatives to replace synthetic refrigerants in future heat
pumping systems. However, carbon dioxide has the advantage of being safe.
The need for air conditioning has been on continuous rise in the past decades in Sweden
and expected to rise even more in the future due to increasing outdoor temperature
because of global warming. Therefore, heat pumps for space heating are also expected to
run in reverse mode and provide air conditioning.
The increasing average outdoor temperature makes the air source heat pumps a more
attractive solution in Sweden, especially with the quieter new air heat exchangers.
Aim of the project
Investigate the performance of a large-scale reversable heat pump in a commercial
building. The heat pump has air as the heat source and work with carbon dioxide as the
refrigerant.
Compare the performance analysis from the field measurement data with the results of
computer modelling.
Use modelling to compare the performance of the heat pump solution with carbon dioxide
to heat pumps with ammonia and propane, and to other heating alternatives.
Preliminary tasks:
- Conduct literature review on heat pumping systems with natural refrigerants.
- Process the field measurement data and run performance analysis of the system.
- Build computer models of the heat pump systems with carbon dioxide, ammonia, and propane.
- Compare results from the field measurements analysis with results from the modelling.
- Suggest improvement if to system operation and control, if necessary.
- Run theoretical comparison among systems with carbon dioxide, ammonia, and propane
- Run techno-economic and environmental analysis comparing the alternatives with natural refrigerants to conventional alternatives.
Preliminary proposed time schedule
The project starts in January or February 2023. The expected thesis period is 5 months. At
start of the thesis work the student is expected to submit a detailed work plan and
preliminary layout of the thesis report.
No intermediate reports are required; however, the student is encouraged to write the
report in parallel to conducting the research.
Besides the final presentation, at least one presentation will be conducted around halfway
of the project period in a project meeting with the industrial partners.
Contact persons and Industrial partners:
Supervisor and examiner at KTH, Department of Energy Technology
Contact person and the industrial partner: