TITLE:
Analysis of Thermodynamic Characteristic Changes in Direct Expansion Ground Source Heat Pump Using Hydrofluoroolefins (HFOs) Substituting for HFC-134a
AUTHORS:
Yuefen Gao, Honglei Zhao, Yingxin Peng, Tony Roskilly
KEYWORDS:
Direct Expansion Ground Source Heat Pump (DXGSHP); Thermodynamic Performance; HFO-1234yf; HFO-1234ze[E]; HFC-134a
JOURNAL NAME:
Energy and Power Engineering,
Vol.5 No.2A,
April
29,
2013
ABSTRACT: HFO-1234yf and HFO-1234ze[E] have low global warming potential and
zero ozone depletion potential. If they are used in the direct expansion ground
source heat pump system substituting for HFC-134a, the system will be
beneficial to mitigating climate change. This study aims to find out the
thermodynamic characteristics of the direct expansion ground source heat pump
system using HFO-1234yf or HFO-1234ze[E] by theoretical calculation. The
results indicate that HFO-1234yf system in an actual cycle has the highest COP.
HFO-1234yf and HFO-1234ze[E] have such smaller capacity per unit of swept
volume that they need larger compression capacity if providing the same heating
or cooling loads. For a given unit when HFC-134a is replaced with HFO-1234yf or
HFO-1234ze[E], the capacity will decrease. More refrigerant charge is required
in the HFO-1234yf or HFO-1234ze[E] system. The results also present that more
refrigerant charge is required in the cooling mode than in the heating mode.