In this study, a PVT based solar assisted ground source heat pump (SAGSHP) system was investigated regarding its energy performance and cost-effectiveness for the city of Thessaloniki (Greece). The SAGSHP system was set to cover the space heating and domestic hot water needs for a low-rise dwelling. A mathematic model formulated in TRNSYS was used with the aim to carry out parametric analysis by varying the number of the PVTs. It is worth noting that, two of the most important components of the employed model, the PVT collector and the geothermal heat exchanger, have already been validated via experimental data. Simulations were conducted and through the results seven energy metrics were estimated, with the objective to examine the system’s energy performance from various perspectives. The SAGSHP system with 16 PVTs was found capable to covering 73% of the heating load and to generate 1.22 times more electricity than that consumed by the system. The electricity yield of PVTs was not affected throughout the parametric analysis, and the maximum specific productivity was estimated at 301.5 kWh PVT per year. The results suggest that a SAGSHP system equipped with about 14 PVTs can reach energy self-sufficiency. As regards the economics of the SAGSHP system, this was compared with a natural gas boiler system via two methods, the life cycle cost (LCC) and the life cycle savings (LCS). A sensitivity analysis with major economic parameters of the systems was carried out. It was found that the cost-effectiveness of the SAGSHP system is influenced mainly by its capital cost and by the price of the natural gas. Systems equipped with less than 12 PVTs can be cost-competitive by subsiding from 8% up to 42% of their capital cost. Also, system with more than 12 collectors were found of more benefit than the smaller ones, in the case where feed-in-tariff schemes are applied, or the bank loan’s interest rate is low. It can be concluded that, the proposed system can be an attractive monetary solution for covering the heating load in comparable dwellings with a similar climate to Thessaloniki.

中文翻译：

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地中海北部城市太阳能辅助地源热泵系统的能源和经济评估


在本研究中，对塞萨洛尼基市（希腊）基于 PVT 的太阳能辅助地源热泵 (SAGSHP) 系统的能源性能和成本效益进行了调查。 SAGSHP 系统旨在满足低层住宅的空间供暖和生活热水需求。使用 TRNSYS 中制定的数学模型，旨在通过改变 PVT 的数量来进行参数分析。值得注意的是，所采用模型的两个最重要的组件，PVT 收集器和地热热交换器，已经通过实验数据进行了验证。进行了模拟，并根据结果估计了七个能源指标，目的是从不同角度检查系统的能源性能。具有 16 个 PVT 的 SAGSHP 系统被发现能够覆盖 73% 的热负荷，产生的电力是系统消耗的 1.22 倍。在整个参数分析过程中，PVT 的发电量并未受到影响，PVT 的最大比生产率估计为每年 301.5 kWh。结果表明，配备约14个PVT的SAGSHP系统可以实现能源自给自足。至于 SAGSHP 系统的经济性，通过生命周期成本 (LCC) 和生命周期节省 (LCS) 两种方法与天然气锅炉系统进行了比较。对系统的主要经济参数进行了敏感性分析。研究发现，SAGSHP 系统的成本效益主要受其资本成本和天然气价格的影响。配备少于 12 个 PVT 的系统可降低 8% 至 42% 的资本成本，从而具有成本竞争力。 此外，在应用上网电价补贴计划或银行贷款利率较低的情况下，超过 12 个收集器的系统比较小的收集器更有利。可以得出的结论是，所提出的系统可以成为一种有吸引力的货币解决方案，用于覆盖与塞萨洛尼基气候相似的可比住宅的热负荷。