This thesis is an analysis of the simulated performance of two indirect heat pump assisted solar domestic hot water (i-HPASDHW) systems compared to two base systems: an electric domestic hot water (DHW) system and a traditional solar domestic hot water (SDHW) system. In this study, the four systems of interest were modeled in the TRNSYS software and simulated for a year in order to compare their performances. All of the systems had the same load profile and aimed to deliver domestic hot water at a constant temperature. This insured that each system delivered approximately the same amount of energy for the simulated period, thereby creating a common basis for comparison. The heat pump was introduced into the system configuration in an attempt to further improve the performance. Theoretically, the heat pump should send colder fluid to the collector which will extend the solar collection periods, both daily and seasonally when compared to the traditional SDHW system, as well as increase the efficiency of the collector. This will help to reduce the reliance on the electric auxiliary heaters and thus decrease the total electricity consumption. Both i-HPASDHW systems considered for this thesis collected more solar energy over the course of the simulated year compared to the base traditional SDHW system. They also consumed less electricity than the two base systems, which directly correlated to lower annual operating costs. It was concluded that the two i-HPASDHW systems analyzed in this study proved to be feasible configurations that performed more efficiently than the two base systems under the simulation conditions. However, it is important to understand that the results presented apply to the specific configurations. While the potential has been shown, prototypes must be built and tested with properly sized equipment for specific applications to get an accurate idea of the potential benefits. Also, equipment costs must be considered to determine payback periods for each system.

Hybridization and electrification of modern vehicles is today a reality. This effects the construction of the heating and cooling systems in vehicles where earlier the waste heat from the combustion engine was a great heat source. Heat pump systems are commonly used in heating systems in buildings and can therefore also be used for heating the cabin and different components in a vehicle. Modelling a heat pump system and performing simulations gives the advantage of investigating the heating performance of the heat pump during certain conditions. In this master thesis, which is performed in a pre-study project that is performed under the Swedish Electromobility Centre, a heat pump is modelled and the heating performance when changing the vapour quality is investigated during cold environments. Also how the heating capacity for different refrigerants and changing size and speed of compressor is simulated. With the methods and assumptions used, especially isentropic compression, the results shows that decreasing the vapour quality increase the mass flow in the heat pump circuit but the decrease in specific heating is larger which results in an overall decrease in heating capacity. The goal of 10 kW heating capacity can be achieved by increasing the compressor size or make use of waste heat from other vehicle components.

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Heating, Ventilating and Air Conditioning Systems (HVAC) are not only one of the most energy consuming components in buildings but also contribute to green house gas emissions. As a result often environmental design strategies are focused on the performance of these systems. New HVAC technologies such as Geothermal Heat Pump systems have relatively high performance efficiencies when compared to typical systems and therefore could be part of whole-building performance design strategies. In collaboration with the Virginia Tech Corporate Research Center, Inc., this research studies the energy consumption and cost benefits of the Geothermal Heat Pump System that has been integrated and operated in the KnowledgeWorks I and II buildings located on the Virginia Tech campus. The purpose of this thesis is to understand the energy and cost benefits of the Geothermal Heat Pumps System when compared to the conventional package variable air volume (VAV) with hot water coil heating and air-source heat pump systems using computer simulation and statistical models. The quantitative methods of building energy performance and life-cycle cost analyses are applied to evaluate the results of simulation models, the in-situ monitoring data, and the associated documents. This understanding can be expanded to the higher level of architectural systems integration. / Master of Science

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Det här är ett examensarbete som handlar om en fastighet som står på Norra Kungsgatan 37-43 som har både en värmepump och fjärrvärme för uppvärmning. Värmepumpen används i första hand och fjärrvärmen används som spets när värmepumpen inte räcker till. Detta är en ganska ovanlig kombination. Syftet med arbetet är att ta reda på om detta är en bra lösning och om lösningen är lönsam. För att få fram hur stort fastighetens energibehov är så görs beräkningar utifrån fjärrvärmedata från tidigare år samt en gammal värmepump som är utbytt sedan 2011. Byggnadens energibehov uppskattas vara ungefär 895 MWh/år och värmepumpen beräknas täcka 54 % av värmebehovet. Utifrån detta jämförs sedan kostnaden för uppvärmning av fastigheten med endast fjärrvärme med kostnaden för uppvärmning med både värmepumpen och fjärrvärme. Genom att använda värmepumpen så sparas drygt 140 000 kr per år. Det innebär att värmepumpen är lönsam rent ekonomiskt. Däremot kan användningen av högkvalitativ energi för uppvärmning diskuteras. Värme som är energi med lägre kvalitet borde i första hand användas för uppvärmning. Det för att inte slösa på våra dyrbara energiresurser och på så sätt få en hållbar utveckling. / This is an essay about a property at Norra Kungsgatan 37-43 who is heated with both a heat pump and district heating. The heat pump is used primarily and district heating is used as a tip when the heat from the heat pump is not enough. This is a pretty rare combination. The purpose of this essay is to find out if this is a good solution and if the solution is economically viable. To determine the heat demand of the property, calculations based on district heating data and heat pump data from previously years has been used. The heat demand of the building is estimated to be approximately 895 MWh/year and the heat pump is estimated to cover 54% of the heat demand. Based on this, the cost for heating the building with district heating is compared with the cost of heating the building with the heat pump and district heating. By using the heat pump, more than 140 000 kronor per year can be saved. This means that the heat pump is economically viable. However, the use of high-quality energy for heating is discussed. Heat is energy with lower quality and should be used primarily for heating. We can not waste our precious energy resources if we want to achieve sustainable development.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains ix, 92 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 72-75).

A detailed investigation of novel air-coupled absorbers for use in a diesel engine exhaust-driven ammonia-water absorption system operating in extreme ambient conditions was conducted. Electrically driven vapor-compression systems are under scrutiny due to the environmental impact of synthetic refrigerants and the exacerbation of electric utility loads during peak demand periods. One alternative to vapor-compression systems is the absorption heat pump that uses environmentally benign working fluids and can be driven by a variety of heat sources, including waste heat and solar thermal processes. Direct air coupling of the absorber and condenser instead of indirect hydronic coupling can reduce absorption system size, complexity, and inefficiency, but materials compatibility issues with ammonia-water and the poor heat transfer properties of air present challenges. Heat and mass transfer modeling was used to predict the performance of round-tube corrugated-fin and compact tube-array absorbers designed for a 2.64-kW absorption chiller operated in high ambient temperature (51.7°C) conditions. A single-pressure ammonia-water test facility was constructed and used in conjunction with a temperature- and humidity-controlled air-handling unit to evaluate the absorbers at design and off-design operating conditions. Absorber performance was recorded over a range of air temperatures (35-54.4°C), air flow rates (0.38-0.74 m3 s-1), inlet solution temperatures (92-102°C), concentrated solution flow rates (0.006-0.010 kg s-1), and concentrated solution concentrations (38-46%). At design conditions, round-tube corrugated-fin absorbers of 394 and 551 Fins Per Meter (FPM) demonstrated comparable performance (Q394-FPM,exp = 4.521±0.271 kW; Q551-FPM,exp = 4.680±0.260 kW), and measured heat transfer rates were 0.7-1.9% AAD higher than those predicted through modeling. The measured heat transfer rate in the prototype tube-array absorber was significantly lower than the values predicted at design conditions (Qprot,exp = 2.22±0.24 kW; Qprot,mod = 4.33 kW). Maldistribution of the two-phase flow in the tube array is the probable cause of the disparity between the prototype absorber data and model predictions. Results from this investigation can be used to guide the development of air-coupled heat and mass exchangers for compact absorption heat pumps.

Solar Domestic Hot Water systems and air-source heat pumps offer the potential for energy savings in residential hot water production, however their performance is limited in cold climates, where the low ambient temperature reduces the collector efficiency or the heat pump coefficient of performance. Combining these systems into a Solar-Assisted Heat Pump can alleviate these limitations by reducing the required collector temperature and by providing an increased heat pump evaporator temperature. This study is a continuation of the development of an Indirect Solar-Assisted Heat Pump undertaken at the Queen’s University Solar Calorimetry Laboratory. Previously, a numerical study compared its performance to existing technology, and based upon this feasibility analysis, a prototype was constructed for controlled laboratory tests using simulated solar input. In the current study, the prototype was modified to include a novel hybrid collector such that its performance under actual weather conditions throughout the year could be assessed. On sunny days, the system experienced daily averaged collector efficiencies between 0.47 and 0.88, depending on the flow rate and season. Averaged heat pump coefficients of performance of 2.54 to 3.13 were observed. Overcast days experienced reduced coefficients of performance, between 2.24 and 2.44. However, on overcast days, upwards of 76% of the collected energy gain was from convection with the surroundings. Based upon these experimental results, a model for the hybrid collector was developed. Annual simulations of the system were conducted to compare the performance of the solar heat pump system when fitted with the hybrid collector relative to cases with more conventional glazed and unglazed collectors commonly used in solar thermal systems. Results were produced for three Canadian cities: Toronto, Vancouver and Winnipeg. The heat pump with the hybrid collector outperformed the other collectors in the Toronto climate, with a free energy ratio of 0.548. Adding a thermally controlled valve to the hybrid collector was proposed to further increase the annual free energy ratio, and was shown to perform best in all three cities, with free energy ratios of 0.558, 0.576 and 0.559 for Toronto, Vancouver and Winnipeg, respectively. It is proposed that additional improvements could be achieved by allowing the collectors to deliver heat directly to the storage tank, by circumventing the heat pump if the conditions were favorable. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-01-06 13:44:41.77