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Advantages and Limitations of Ground-Source Heat Pump Systems
Published in Vasile Minea, Heating and Cooling with Ground-Source Heat Pumps in Cold and Moderate Climates, 2022
Long-term maintenance costs of buildings equipped with ground-source heat pump systems could be 38 to 56% lower compared to those of buildings provided with conventional HVAC systems (e.g., US$1.45/m2/year versus US$2.58 to US$3.77/m2/year), mainly because: (i) most parts of the ground-source heat pump systems remain protected underground or indoors, while in the case of air-source heat pumps, parts of the system are outdoors, exposed to the elements and potential mechanical damage and the technical lifetime expectance lasts about 15 years; (ii) there is no requirement for annual safety inspections as there is for combustion equipment; (iii) there are few moving parts; (iv) fluid circulation pumps are guaranteed for more than one year and easy to replace; (v) long geothermal heat pumps’ compressors technical life of up to 15 years (25 years for scroll compressors, guaranteed for up to 5 years); (vi) hermetically pre-sealed refrigerant circuits of geothermal heat pumps containing relatively small quantities of refrigerant. For less than 3 kg of refrigerant charge, little maintenance should be required; however, large-capacity geothermal heat pumps containing more than 6 kg of refrigerant, or direct expansion systems containing more than 3 kg of refrigerant, require regular checking for leaks; (vii) the expected technical life of ground-coupled heat exchangers constructed with polyethylene and coated copper tubing is expected to be over 50 years and 30 years, respectively, and be, virtually, maintenance free.
Introduction
Published in Hui Huang, Heat Pumps for Cold Climate Heating, 2020
Hui Huang, Xiangfei Liang, Bo Zheng
When the air source heat pump water heater produces domestic hot water, in most cases, it is connected with a water tank, within which the hot water is stored and discharged from when needed. Anyway, the air source heat pump water heater has the obvious advantages of energy saving, environment protection, economy and safety, etc. Under the same heating capacity, although it has a higher initial investment, electric energy consumption is usually less than one third of that of the electric water heater and electric boiler, effectively reducing the consumption of high-grade electric energy. Compared with the natural gas water heater and natural gas boiler, the air source heat pump water heater is safer, more reliable and convenient to operate. Furthermore, compared with solar water heater, it is relatively less affected by the weather, and can produce hot water 24 hours in all weather conditions.
Chillers and Heat Pump Cycles and Systems
Published in T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl, Heating and Cooling of Buildings, 2016
T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl
The performance of heat pumps is highly sensitive to the operating conditions. The efficiency of most air-source heat pumps drops dramatically at low temperatures, generally making them unsuitable for cold climates. The ground offers a convenient alternative to ambient air as a source of heat at temperatures closer to the space to be heated or cooled. The deep soil temperature year-round is fairly constant and close to the annual outdoor air temperatures. The large fluctuations in ambient air temperatures during the year that impose a severe penalty on cycle efficiency can thereby be greatly reduced. Ground-source heat pumps* is a broad term that applies to a variety of systems using heat from the ground soil or heat from surface or underground water (Kavanaugh and Rafferty, 1997).
Monte Carlo simulation approach to understand the cost variance for energy retrofit projects: comparative study of Finland and the United States
Published in Construction Management and Economics, 2022
Ming Hu, Eero Nippala, Kari Kallioharju, Sofie Pelsmakers
However, in the United States, the majority of residential buildings depend on a central furnace for heating. Warm air is circulated through the buildings through ducts, thus it is often called a forced air system. It can be powered by electricity, natural gas, or fuel oil (Smart House). The heat pump system, especially newer ground source heat pump systems, is not well known in the US building and construction industry. For buildings with high heating energy consumption, a ground source heat pump’s energy-saving potential is larger than that of an air source heat pump (Häkämies et al. 2015). When a ground source heat pump system needs to be integrated with other building systems, the US contractors are less familiar with such system installation compared to the Finnish contractors. However, the air source heat pump is gaining rapid adoption in renovation projects in some regions in the US. For example, as of 2018, it was estimated that over twenty thousand New England homes and businesses installed air source heat pumps using incentive programs (Cape Light Compact 2020). This lack of knowledge and experience of ground source heat pumps is directly linked to an increase in risk and uncertainty, consequently contributing to higher construction costs, a higher probability of cost overrun, and a higher probability of project schedule overrun.
Study of thermal performance of air-source heat-pump heating for suburban residential buildings in Beijing
Published in Science and Technology for the Built Environment, 2020
Xiaoling Yu, Qian Lv, Lu Zhang, Xiaolin Wang, Xiangzhao Meng, Zhenghua Zong
The application of air-source heat-pump heating to replace conventional coal-combustion heating in winter has many advantages, including a clean environment, high efficiency, and safety. However, it also faces a few challenges in terms of the design of heat pumps and management of peak electric load in current electric grids. In the design of electrically driven heat-pump heating for buildings, the first task is to evaluate the heating load of the building, which is dominated by outdoor weather conditions and building structure, including roof design, external wall configuration, and insulation thickness. Many researchers have demonstrated that building energy load can be estimated using dynamic thermal balance models based on coupled weather data and the building energy transfer (Ortiz et al. 2017; Salamanca et al. 2013). Crawley et al. (2008) reviewed and compared the capabilities of different building energy performance simulation programs. In the building energy load calculation, one of the key parameters is the dynamic convective heat transfer coefficient (CHTC) of the exterior surface of a building, which depends on outdoor climate conditions and has large effects on the calculation of heating load. Much effort has been put in the study of CHTC (Defraeye, Blocken, and Carmeliet 2011; Mirsadeghi et al. 2013; Mavromatidis 2016; Yang, Zhu, and Liu 2017). Empirical correlations, numerical simulations, and experimental tests are the general methods that are currently used to estimate the CHTC for different applications.
Energy-efficient effect evaluation of air-source heat pump engineering in a hotel
Published in International Journal of Ambient Energy, 2022
Zhonglan Hou, Xinli Wei, Shuman Guo, Aiping Zhang, Xiang Qin, Bingxue Zhang
Hot water consumption is huge, so there is excellent energy-saving potential and massive benefit using air-source heat pumps to produce hot water. Long, Gang, and Fengchang (2013, 31) compared the economic efficiency in several heat source hot water systems , and analysed the energy-saving effect of solar-assisted heat pump hot water system. The annual average of hot water per ton was 9.96 Yuan/t. The study was designed to evaluate the techno-economic feasibility of its application to single-detached homes in Canada (Udovichenko and Zhong 2020, 26).