Renewable energy systems have received considerable attention as a sustainable technology in the building sector. Specifically, the use of ground-source heat pump (GSHP) and air-source heat pump (ASHP) for heating and cooling of buildings is increasing rapidly, and the combination with photovoltaic (PV) systems and heat pump systems provide energy savings and environmental benefits. This study investigates the feasibility of replacing conventional heating and cooling systems in a multifamily, residential building with GSHP and ASHP systems and their combination with PV. The integration of PV with GSHP and ASHP systems presents an opportunity for increased solar energy usage resulting in a reduction of electricity demanded and a reduction of emissions of greenhouse gases. To analyze different heat pumps systems with and without PV, system modeling and computer simulations are performed with RETScreen Expert software.<div><br></div><div>A multifaceted verification and validation study is conducted for the system model and computer simulation. The important objective of this part of the study is to understand and develop confidence for modelling individual studies in RETScreen Expert software. To accomplish this, RETScreen Expert is used for modeling and simulating the performance of PV systems in several geographical locations, including Fort Wayne, IN. A comparison is made to performance predictions from System Advisory Model (SAM) software. In addition, a study is done to compare predictions from both software to previously published data.<br></div><div><br></div><div>In the further phase of the study, eQUEST software, a tool for building energy simulation is used to predict outputs such as electricity consumption, heating loads, and cooling loads for the multifamily residential building considered in this study. These outputs, as well as, building parameters are used as inputs to RETScreen Expert. Since, this study focuses on modeling and simulating the heating and cooling systems coupled with PV for feasibility analysis, only a few minor modifications to the eQUEST default settings are made.<br></div><div><br></div><div>The outputs from eQUEST are used as inputs to RETScreen Expert and analysis of ASHP and GSHP systems, as well as their combination with a PV system are performed. The results include the technical performance and financial model of each system, which can be used to indicate feasibility. The results show that both GSHP and ASHP systems are environmentally friendly and reduce energy consumption. These systems are economically feasible, with payback periods of under 10 years, when electricity prices are high. When combined technology is preferred, PV-GSHP systems are more environmentally friendly and have fuel savings far better than any other proposed systems. But the feasibility of the both the GSHP and PV-GSHP systems strongly depends on loop installation cost.<br></div>

Nine pages of Addenda and eight pages of Errata in back pocket. / Includes bibliographical references. / vii, 192, [78] : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1994

M. Tech. Mechanical Engineering / Discusses the main objective of this research was to perform an experimental investigation into the heat pump drying performance of biomaterials in South African environmental and climatic conditions.Specific objectives to meet the main goal are: to design and construct a heat pump dryer (HPD) according to local conditions; to set up experimental tests and examine the effect of other vital operating conditions such as relative humidity, drying air velocity and ambient temperature; and to analyse the data in terms of the thermal performance of the heat pump and the drying performance of the dryer

M. Tech. Mechanical Engineering. / Objectives of this research is to investigate the theoretical performance of the heat pump water heating system using R134a and R404A; to investigate effects of superheating and sub-cooling on the COP and energy consumption of the heat pump system; and to validate the theoretical findings with the experiment results, using the selected environmentally friendly refrigerants.

The motivation of the research presented in this thesis was to investigate the potential of using a commercial 2.3 kW heat pump dehumidifier (HPD) simultaneously as a dryer for high-moisture agricultural products and for other domestic dehumidification/heating applications. A drying system incorporating the HPD was designed and constructed, along with instrumentation to gather data on the properties of process air as well as real-time weight of the material being dried. The HPD was equipped with an external water-cooled condenser that rejected excess heat out of the system. The design of the system allowed for conducting drying with recirculation of air as well as use of electrical heaters. In an open mode, the drying could be carried out simultaneously with room dehumidification and water heating in the secondary condenser. / The drying experiments were conducted with apple, tomato and agar gels. The system was found to be more effective in drying of material with higher amount of free moisture such as tomato. Comparisons were made between HPD assisted drying (partial and complete) and hot air drying (at 45°C and 65°C) in the same system using apple as the test material. Colour changes (L*a*b* values) in the samples were compared between treatments. It was observed that the degree of undesirable colour change was least in case of the HPD assisted system. The HPD dried fruit exhibited better rehydration properties than the hot air dried samples. Water activity of the HPD dried samples was noticeably lower than that of the hot air dried samples at the same water content, indicating that the residual moisture was probably held under higher tension. Histological observation indicated that there was a lesser degree of damage to the cellular structure of apple when dried with the HPD than when dried with hot air alone. / In terms of energy consumption, the process of HPD assisted drying is more expensive. Much of the energy input is rejected at the secondary condenser as excess heat. Unless this heat is recovered for another purpose, or the system is modified to reuse it for drying, the drying process must carry this loss entirely. The specific moisture extraction rate (SMER) for apple was as low as 0.1 kg per kWh with the HPD assisted system. The SMER values for drying at 45°C was 0.5 kg per kWh and was almost 0.8 kg per kWh at 65°C. / The HPD assisted drying system demonstrated the ability of heat pumps to link different energy related activities viz., drying, space dehumidification and water heating. The energy expenditure is expected to be impressive when considered for all the related applications. The concept of utilizing heat pumps on farms to link up different energy streams for better utilization of the low-grade heat sources is discussed. A possible drying efficiency assessment in the form of energy-based evaluation is proposed.

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Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Makina Mühendisliği Anabilim Dalı, 2008. / Bibliyografya var.

An air source heat pump (ASHP) water heater is a renewable and energy efficient hot water heating technology. ASHP water heaters are fast gaining maturity in the South African market and in Africa at large due to their low energy consumption (about 67 percent lower than conventional geysers), relatively low installation and operation cost, their environmental friendly nature and possibly the ease to retrofit with the old inefficient technologies. Furthermore, ASHP water heaters make use of some of the most recent advancement in refrigeration technologies enhancing their performance through a wide range of weather conditions. However, residential ASHP water heaters which come at the tail of a series of highly sophisticated models still harbour primitive control designs. One of such control system is the intermittent (on/off) control whereby the ASHP unit responds to a temperature differential threshold rather than instantaneous temperature fluctuations. Unfortunately, this control method contributes to a rapid deterioration of the compressor and other actuators due to high starting current during transient states and partial loading. Capacity control is a better alterative as it offers a more reliable system’s performance as well as a better protection for the system components. However, the drawbacks of implementing such a technology on residential ASHP water heaters is the initial purchasing cost. We use a systematic approach in this research to circumvent the purchasing cost and complete redesign hysteresis. The first step was centered around a hypothetical analysis of the performance of the heat exchangers in a bid to uncover the weakness during the operation of a residential ASHP water heater. It was observed that at ambient temperatures above 22°C notably during summer and winter afternoons, water only harnesses about 75 percent of the total heat rejected. Furthermore, the actuators keep doing work for about 15-20 minutes even after the heat transfer process has ceased completely. Following these observations, a sequential flow algorithm was developed aimed at matching the consumption point to weather variables like ambient temperature and secondly to most efficiently synchronize actuator components for a better energy management. This novel control method can save up to 58 percent of energy compared to the conventional on/off method during summer afternoons and averagely 20 percent during the rest of the day. It also has the merit to be cost effective as it barely requires no component retrofitting.

Globally, there is growing concern about energy consumption and its diverse effects on the environment. In South Africa, the current status quo is unfavourable in the domain of energy, hence the Department of Energy, Eskom and NERSA have embarked on supporting energy efficiency technologies nationwide as a strategic goal in reducing demand on the national grid. Due to the non conservative consumption of electricity from the grid and the insufficient supply to meet its demand, the importation of crude oil is very certain. In addition, the current and most popular technology for pool water heating in the said country is the resistive element which is inefficient and non-cost-effective. The energy consumption of residential swimming pool water heating is very massive, and tariff structure shows a constant rise. Furthermore, there's a current electricity crisis during the Eskom evening peak. Hence, a reliable, efficient, cost-effective and renewable energy technology such as an air source heat pump is required as a retrofit to the existing resistive element. Furthermore, mathematical modelling is a tool that can be used to mimic the dynamic behaviour of a physical or process system. It is a computational language or mathematical equation used to predict the dynamic behaviour of physical systems [Tangwe et al., 2015]. Various methods such as numerical methods have been considered as the particular types of mathematical modelling which have been employed to predict the performance of swimming pool ASHP water heater. However, they were unreliable and expensive. Consequently, this research focused on the experimental determination of the viability and development of a mathematical model to predict the performance of swimming pool ASHP water heater. The benefit of the development and building of this model was attributed to its low cost and credibility to forecast the performance of swimming pool ASHP water heater. Also, this robust mathematical model can be used by an energy service company and system manufacturer to compute the dynamic coefficient of performance of the swimming pool ASHP water heater. Following the above-mentioned information, the research sought to provide a permanent solution to the Eskom evening peak constraint. This is because energy-efficiency, serves as the bridging block between conventional and renewable energy sources needed by Eskom in a bid to provide a balance energy mix and sustainable energy. The implementation of a swimming pool ASHP water heater guaranteed a conducive environment for the population due to the reduction in environmental pollution.

M.Ing. / Heat pump water heaters (HPWHs) have been identified as a viable replacement for electrical resistance heaters due to their high efficiency and reliability. Heat exchangers are a crucial part of HPWHs, and play a vital role in improving the system's coefficient of performance (COP). Experimentally analysing a heat exchanger is usually a slow and highly labour intensive practice since vast amounts of data have to be logged and mathematically manipulated to obtain results. A lot of time and money could be saved, if this process were to be automated. The first objective of this study was to develop a software program capable of calculating the heat transfer correlation constants of a tube-in-tube heat exchanger using the modified Wilson plot technique from data obtained through water-to-water experimentation at different flow rates and temperatures. The data was to be captured by using data acquisition equipment capable of measuring temperature from several Ptl 00-type temperature sensors, pressure transducers as well as Coriolis flow meters, all within a few seconds, thus giving virtually steady-state measurements. The second objective of this study was to develop a software package, capable of capturing and manipulating data from a HPWH system using the same tube-in-tube heat exchanger and using R-22 as refrigerant. The software package had to be capable of capturing all the required experimental data from the system and calculate the local and average heat transfer coefficients on-line and display it to the user. It also had to capture it in the form of a spreadsheet data file for further manipulation. The success of the software package would depend on the results achieved, as well as the time saved with its implementation. To verify the results, the output of the program was compared with the findings of various other researchers. It was found that the output of the program compared well with the results obtained by other researchers, both for the average heat transfer coefficient as well as the local heat transfer coefficients. The time taken for a full set of data was as little as 30 minutes, compared to many hours previously needed to achieve stable results. The software package has thus succeeded in fulfilling its objective to reduce the time taken to achieve accurate results during heat transfer experimentation.