Naslov
Steady-state heat rejection rates for a coaxial borehole heat exchanger during passive and active cooling determined with the novel step thermal response test method

Autori
Kurevija, Tomislav ; Macenić, Marija ; Strpić, Kristina

Izvornik
Rudarsko-geološko-naftni zbornik (0353-4529) 33 (2018), 2; 1-15

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
shallow geothermal energy, thermogeology, borehole heat exchanger, ground source heat pump

Sažetak
Classic and extended step thermal response test were conducted on three different location in Zagreb. Measurements with the classical thermal response test were used to determine thermogeological properties of the ground and thermal resistance of the borehole for each location. Different values of thermal conductivity are result of differences in geological profile and depth of the sites. In addition, experimental research of steady-state thermal response step test (SSTRST) was carried out to determine heat rejection rates for passive and active cooling in steady state regime. Results showed that heat rejection rate is only between 8-11 W/m, which indicates that coaxial system is not suitable for passive cooling demands. Furthermore, the heat pump in passive cooling mode uses additional plate heat exchanger which causes additional temperature drop of the working fluid by approximately 1, 5 °C. Therefore, steady-state rejection rate for passive cooling is even lower for a real case project. Coaxial heat exchanger should always be designed for an active cooling regime with an operation of a heat pump compressor in a classical vapour compression refrigeration cycle.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo

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