Combining ground source absorption heat pump with ground source electrical heat pump for thermal balance, higher efficiency and better economy in cold regions. (December 2015)

• Record Type: Journal Article
• Authors: Wu, Wei; Li, Xianting; You, Tian; Wang, Baolong; Shi, Wenxing
• Is Part Of: Renewable energy. Volume 84(2015)
• Page Start: 74
• Page End: 88
• Publication Date: 2015-12
• Subjects: Ground source heat pump -- Absorption heat pump -- Hybrid -- Thermal imbalance -- Energy efficiency -- Cold region; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2015.06.025
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Ground source electrical heat pump (GSEHP) and ground source absorption heat pump (GSAHP) have opposite characteristics on thermal imbalance and primary energy efficiency (PEE) in cold regions: (1) GSEHP leads to cold accumulation while GSAHP may cause heat accumulation in the warmer part of cold regions; (2) GSEHP has higher PEEs in cooling mode while GSAHP has higher PEEs in heating mode. The hybrid GSAHP-GSEHP is proposed to counteract the disadvantages and combine the advantages. Different combinations of heating and cooling supply ratios contributed by GSAHP in a hybrid GSAHP-GSEHP can maintain good thermal balance with soil temperature variations within 0.2 °C/year. The influence of supply ratios on thermal imbalance ratio (IR), annual primary energy efficiency (APEE) and economy are investigated to select some preferred configurations of GSAHP-GSEHP, which will be modeled and dynamically simulated over 20 years. Results show that a bigger heating supply ratio of GSAHP and a more negative IR contribute to higher APEEs and fewer boreholes within acceptable IRs of ±20%. Compared with GSEHP, the APEE enhancement is 10.9–34.6%, the energy saving rate is 9.8–25.7%, the lifecycle cost (coal) reduction is 3.7–22.0%, and the lifecycle cost (gas) reduction is 4.1–12.1%. The GSAHP-GSEHP maintains good soil balance with high PEEs in cold regions. Highlights: GSEHP and GSAHP have opposite features on thermal imbalance and energy efficiency. Hybrid GSAHP-GSEHP can counteract the disadvantages and combine the advantages. Various GSAHP-GSEHP combinations keep soil temperature changes within 0.2 °C/year. Energy efficiency improvement is 10.9–34.6%, and energy saving rate is 9.8–25.7%. Lifecycle cost reduction is 3.7–22.0% for coal and 4.1–12.1% for gas in 20 years.