Maldistribution in airewater heat pump evaporators. Part 1: Effects on evaporator, heat pump and system level

Gunda Mader, Björn Palm, Brian Elmegaard

Research output: Contribution to journalJournal articleResearchpeer-review


This paper presents an approach to quantify the effect of evaporator maldistribution onoperating costs of air-water heat pumps. In the proposed simulation model maldistributionis induced by two parameters describing refrigerant phase and air flow distribution.Annual operating costs are calculated based on heat pump performance at distinct operatingconditions. Results show that percentage increase of operating costs is similar for thethree considered climate zones, even though the effect of maldistribution on heat pumpperformance varies with operating conditions. Differences in terms of absolute cost increasefor the climate zones arise mainly due to a varying number of operating hours.Absolute cost increase is considerable in the average and especially colder climate zoneand can only partly be reduced by enlarging the evaporator.© 2014 Elsevier Ltd and IIR. All rights reserved.
Original languageEnglish
JournalInternational Journal of Refrigeration
Pages (from-to)207–216
Publication statusPublished - 2015


  • Heat pump
  • Maldistribution
  • Annual performance
  • System modeling
  • Operating costs

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