PhD Defence at DTU Mechanical Engineering

PhD Defence 5th April: "Industrial heat pumps for high temperature process applications"

Tuesday 29 Mar 16


Jonas Kjær Jensen
Senior Researcher
DTU Construct
+45 45 25 19 68

Jonas Kjær Jensen from DTU Mechanical Engineering defends his PhD, "Industrial heat pumps for high temperature process applications. A numerical study of the ammonia-water hybrid absorption-compression heat pump", Tuesday, 5th April, at 13:00. The defence takes place in Auditorium 38, Building 306, at The Technical University of Denmark. Principal supervisor is Associate Professor Brian Elmegaard and co-supervisor is Associate Professor Wiebke Brix Markussen.

Industrial processes often consume large quantities of heat, while often dissipating large quantities of waste heat to the ambient. The main energy source for industrial heat supply is fossil fuels, either oil or natural gas. Thus, the heat consumption of industrial processes often entail large CO2 emissions as well as emission of other harmful pollutants. As heat pumps can upgrade low temperature waste heat to a high temperature heat supply using only a fraction of primary energy, heat pumps may be applied to improve the energy efficiency of industrial processes. Further, Replacing oil or gas burners with heat pumps could lead to a reduction of the emissions, especially in a future energy system with a high penetration of renewable energy sources. Many industrial heat pumps have been installed with a heat supply temperature ranging from 50 - 90 ◦C. The lack of installation in the temperature domain in excess of 90 ◦C is believed to be caused by the lack of cost efficient heat pumps, rather than a limited demand. Commercial components for industrial heat pumps are limited to a working pressure of 28 bar, although high pressure alternatives do exist for ammonia (50 bar) and CO2 (140 bar). Most commercial compressors are not durable at compressor discharge temperature above 180 ◦C. Using these components, vapour compression heat pumps (VCHP) are limited to heat supply temperatures between 80 - 90 ◦C. Developing heat pumps that are capable of delivering temperatures above 90 ◦C may therefore allow heat pump implementation in more industrial processes than is currently possible. Read full text abstract.

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