Naslov
Optimal sizing of borehole heat exchangers

Autori
Ruševljan, Miroslav ; Soldo, Vladimir ; Ćurko, Tonko

Izvornik
Strojarstvo (0562-1887) 51 (2009), 5; 473-480

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, prethodno priopćenje, znanstveni

Ključne riječi
borehole heat exchanger; ground thermal conductivity; heat pump; long-term temperature changes; optimal sizing

Sažetak
The heat pumps coupled to the borehole heat exchangers (BHE) can serve for heating and/or cooling of buildings. Optimal sizing of BHE is important because of high drilling costs and importance of matching borehole thermal capacity with the capacity of the heat pump. Proper design of such systems is usualy based on complex mathematical simulations that have to be performend not only for peak building loads, but also for building loads that are calculated throughout the whole year. For this reason the building loads have to be analysed in more detail than for sizing of a conventional system. Designers of heat pumps systems coupled to the BHE should also take into acount the long-term temperature changes in the ground surrounding the BHE, which would influence the overall efficiency of the system during its life cycle. The required BHE length is substantially influenced by the thermal conductivity of the ground, that can be only roughly estimated from the local geological data. Experimental thermal response tests provide a good estimate of the ground thermal conductivity and of the borehole thermal resistance. High cost of the thermal response test reduces its application to commercial and institutional objects with the large number of BHE. In this work the overview of calculation methods for the heat pumps coupled to the BHE is presented, with suggestions for optimal sizing of the BHE.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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