Next Article in Journal
Energy Modelling and Automated Calibrations of Ancient Building Simulations: A Case Study of a School in the Northwest of Spain
Previous Article in Journal
Recent Advances in Energy Time Series Forecasting
Article Menu
Issue 6 (June) cover image

Export Article

Open AccessArticle
Energies 2017, 10(6), 810; doi:10.3390/en10060810

Experimental Study on the Performance of Water Source Trans-Critical CO2 Heat Pump Water Heater

1
State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
2
School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
3
Xi’an Jiaotong University Suzhou Academy, Suzhou 215123, China
*
Author to whom correspondence should be addressed.
Academic Editor: Tapas Mallick
Received: 12 March 2017 / Revised: 2 May 2017 / Accepted: 3 June 2017 / Published: 14 June 2017
(This article belongs to the Section Energy Fundamentals and Conversion)
View Full-Text   |   Download PDF [2572 KB, uploaded 15 June 2017]   |  

Abstract

The effect of the discharge pressure on the performance of the trans-critical CO2 heat pump with a low gas-cooler outlet temperature is experimentally investigated on a test rig of water source heat-pump water heater. The optimal discharge pressure of the trans-critical CO2 heat pump is investigated under different external operation conditions. When the tap-water temperature is low, the characteristic of the S-shape isotherm at the supercritical region has little effect on the occurrence of the optimal discharge pressure; while the mass flow rate of CO2, the suction pressure and the gas-cooler outlet temperature play a significant role in determining the emergence of the optimal discharge pressure. At the optimal discharge pressure, the COP reaches the peak; however, the corresponding heating capacity is still lower than its maximum, which is reached as the discharge pressure is slightly above the optimal discharge pressure. Reducing the tap-water flowrate or increasing the water-source temperature can increase the optimal discharge pressure. The COP is positively dependent on both the tap-water flowrate and the water-source temperature. In addition, the tap-water flowrate has a negligible influence on the maximum heating capacity while increasing the water-source temperature can greatly enhance the heating capacity. View Full-Text
Keywords: trans-critical CO2 cycle; heat pump; optimal discharge pressure; COP trans-critical CO2 cycle; heat pump; optimal discharge pressure; COP
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Liu, X.; Liu, C.; Zhang, Z.; Chen, L.; Hou, Y. Experimental Study on the Performance of Water Source Trans-Critical CO2 Heat Pump Water Heater. Energies 2017, 10, 810.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top