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[en] This paper takes the ground source heat pump unit of a research and development centre in Beijing as the research object. This collected the operation data in the cooling condition and the heating condition respectively. Based on the measured data, this paper calculated the coefficient of performances and the energy efficiency ratio of the unit. The results show that when the active chilled beam is used as the air-conditioning terminal device, the inlet temperature of the heat pump unit is greatly improved. The ground source heat pump unit meets the standard and has a higher energy efficiency ratio; The operation of a single unit is more efficient than that of multiple units at the same time. (paper)
[en] In Europe the ground-source heat pump market contracted for the second year running by 2.9% between 2009 and 2010. Around 103.000 units were sold in 2010, taking the number of installed units over one million. The 3 European countries with the most sales are Sweden (31953 units, +16%), Germany (25516 units, -13%) and France (12250 units, -21%). The drop in sales is generally due to market contraction on the current recession but some specificities exist: for instance the insufficient training of the installers has led to under-performance and to a bad image of this energy in France. The Swedish and German manufacturers are in a very strong position and are increasing their market share in the main European markets. (A.C.)
[en] This report presents the results of the collective geothermal heat pumps market. Content: 1 - Surface geothermal energy in 2018 (What exactly is it about?, advantages of geothermal energy, key figures); 2 - Structuration of the sector (actors network, brakes to the development of the sector, legal framework); 3 - Support actions to the sector (space heating funds, Aquapac warranty, regional actions, training); 4 - Perspectives (short- and medium-term perspectives, actors' recommendations); 5 - Synthesis of the study
[en] Highlights: • Advanced exergy analysis performed for a ground-source heat pump (GSHP) drying system. • The performance of components of GSHP drying system was separately analyzed. • The most important system component was the condenser. • 55.3% of the exergy destructions for the overall system were avoidable. • Advanced exergy analysis enables detecting and establishing the improvement priorities. - Abstract: Inefficiencies in an energy system can be quantitatively determined through conventional exergy analysis while sources of the irreversibilities and real improvement potential can be deducted using a relatively new method named as advanced exergy analysis. For the first time, an advanced exergy analysis is applied to a ground-source heat pump (GSHP) drying system used in food drying for evaluating its performance along with each component in this study. The results indicate that the most important system component is the condenser due to the design standpoint. The inefficiencies within the compressor could particularly be improved by structural improvements of the whole system and the remaining system components. Furthermore, the inefficiencies of other system components except for the condenser and the evaporator are mainly affected by the internal operating condition. Both the equipment design and system components’ interactions of the condenser and the evaporator have a significant effect on their inefficiencies. The conventional and modified (advanced) exergy efficiency values are calculated to be 77.05% and 93.5%, respectively
[en] Highlights: • An innovative model for testing combinations of spatial planning and decentralised energy supply. • An improved method of modelling the spatial variability of energy consumption per dwelling type. • Shows how spatial planning would affect the future carbon reduction of decentralised supply. • Forecasts the future carbon reduction and costs of retrofitting and decentralised supply. • A method of forecasting how residential space would affect the suitability of decentralised supply. - Abstract: Low carbon energy supply technologies are increasingly used at the building and community scale and are an important part of the government decarbonisation strategy. However, with their present state of development and costs, many of these decentralised technologies rely on public subsidies to be financially viable. It is questionable whether they are cost effective compared to other ways of reducing carbon emissions, such as decarbonisation of conventional supply and improving the energy efficiency of dwellings. Previous studies have found it difficult to reliably estimate the future potential of decentralised supply because this depends on the available residential space which varies greatly within a city region. To address this problem, we used an integrated modelling framework that converted the residential density forecasts of a regional model into a representation of the building dimensions and land of the future housing stock. This included a method of estimating the variability of the dwellings and residential land. We present the findings of a case study of the wider south east regions of England that forecasted the impacts of energy efficiency and decentralised supply scenarios to year 2031. Our novel and innovative method substantially improves the spatial estimates of energy consumption compared to building energy models that only use standard dwelling typologies. We tested the impact of an alternative spatial planning policy on the future potential of decentralised energy supply and showed how lower density development would be more suitable for ground source heat pumps. Our findings are important because this method would help to improve the evidence base for strategies on achieving carbon budgets by taking into account how future residential space constraints would affect the suitability and uptakes of these technologies.
[en] The double whammy dealt by the economic crisis and housing slump has stifled expansion of the ground-source heat pump market in many European countries. The European Union market contracted for the second year running (by 2.9% between 2009 and 2010), and this despite the fact that more than 100,000 units were sold over the twelve-month period, taking the number of installed units past the one million mark.
[fr]La crise economique ainsi que la crise immobiliere qui touchent de nombreux pays europeens ne facilitent pas l'essor du marche de la pompe a chaleur geothermique. Pour la deuxieme annee consecutive, le marche de l'union europeenne est en baisse (-2,9 % entre 2009 et 2010). il parvient tout de meme a se maintenir au-dessus des 100 000 unites vendues par an, ce qui lui permet de depasser pour la premiere fois le cap du million d'unites installees.
[en] This paper presents a comprehensive exergy analysis of three circuits and whole system of a ground-source heat pump (GSHP) for both building heating and cooling modes. The purpose is to search out the key potential energy saving components. The analytical formulae of exergy loss, exergy efficiency, exergy loss ratio, exergy loss coefficient and thermodynamic perfect degree are derived, respectively. The results show that these exergy indexes should be used integratively, and in the whole system the location of maximum exergy loss ratio is the compressor, while the location of minimum exergy efficiency and thermodynamic perfect degree is the ground heat exchanger, so that the compressor and the ground heat exchanger should be primarily improved. The results also indicate that the exergy loss of a GSHP system for building heating mode is bigger than that of cooling mode, and the exergy efficiency of a whole GSHP system is obviously lower than those of its components for both building heating and cooling modes. Therefore, a comprehensive exergy analysis of a GSHP should be paid more attention to. The results may provide guidelines for the design and optimization of GSHP systems.
[en] Advanced exergoeconomic analysis, the so-called new exergetic approach combined with the economic analysis, is applied to a ground-source heap pump (GSHP) drying system in this study. The thermodynamic inefficiencies and cost performance of the system components are evaluated in parts. Moreover, the results of the advanced exergoeconomic analysis are compared to those of the conventional exergoeconomic analysis. The results show that total costs in the overall system are 4.008 $/h whereas 2.569 $/h of the total costs are avoidable. The avoidable investment costs are significantly lower than avoidable destruction costs. Advanced exergoeconomic analysis indicates that the most important system components are the drying duct and the condenser with respect to reducing the costs. It is possible to reduce 34.6% of the total costs by developing improvement strategies focused on the drying duct and the condenser. It may be concluded that the conventional exergoeconomic analysis is an effective approach to specify the components, in which costs are accumulated while the advanced exergoeconomic approach is essential to determine the cost sources and to develop cost effective improving strategies. - Highlights: • Advanced exergoeconomic analysis is applied to a GSHP dryer for the first time. • Results of conventional and advanced exergoeconomic analyses are compared. • Drying duct and condenser are determined to be the most important components. • Results show that 64.1% of the total costs may be eliminated.
[en] Highlights: • Frost retarding and defrosting studies published in 2000–2017 are reviewed. • Two types of 12 frost retarding measures are classified and analyzed. • 5 defrosting methods and 6 improvement methods are summarized. • Initiation and termination control strategies of defrosting operation are presented. • The existing gaps in the research works are identified and classified as 5 aspects. - Abstract: Air source heat pump (ASHP) units have found worldwide applications due to their advantages of high energy efficient and environmental friendly. Frost deposition and accumulation on the surface of the outdoor coil in an ASHP unit is inevitable and always play significant negative effects. To accurately predict and control a frosting-defrosting cycle, the interrelated heat, mass, and momentum transport phenomena within frost, melted frost and at the air-frost interface, a moving boundary condition, should be clearly understood. This review paper focuses on the developments in frost retarding and defrosting investigations for ASHP units from 2000 to 2017. 12 frost retarding measures and 5 defrosting methods are firstly introduced, followed by 6 typical system optimization methods during reverse cycle defrosting. Alternative control strategies to start and end a defrosting operation are thereby presented. Basing on previous analysis, the existing gaps in the research works on frost retarding and defrosting are identified, and recommendations are finally offered as per the viewpoint of the present authors. This comprehensive and systematic review around an entire frosting-defrosting cycle might provide an overview of the analytical tools for scholars, researchers, product developers, and policy makers, and shed new light on the designing and performance optimization of ASHP units.
[en] The GHEs (ground heat exchangers) is an important element that determines the thermal efficiency of the entire ground-source heat-pump system. The aim of the present study is to clarify thermal performance of a new type GHE pipe, which consists straight fins of uniform cross sectional area. In this paper, GHE model is introduced and an analytical model of new type GHE pipe is developed. The heat exchange rate of BHEs utilizing finned pips is 40.42 W/m, which is 16.3% higher than normal BHEs, based on simulation analyses. (paper)