Due to rising energy costs and increasing environmental awareness, various methods of energy conservation are being investigated. In the residential sector, both solar and heat pump systems have been extensively tested. Recently, combinations of solar and heat pump systems have been developed for both space heating and water heating. These systems have the capability to provide better performances than either of the systems operating on their own. The solar collector benefits from a lower fluid (glycol) inlet temperature which increases efficiencies, and the heat pump benefits from higher evaporator temperatures due to the additional solar energy collected. For this study, a prototype of an Indirect-Solar Assisted Heat Pump for use in the Canadian environment was constructed, instrumented and tested. Controlled, constant temperature tests, as well as solar profile tests were conducted and the heat transfer rates, natural convection flow rate, and heat pump coefficient of performance (COP) were calculated. These values were then compared to simulation results based on a model developed in a previous feasibility study. The experimental COPs calculated ranged from 2.3 to 3.3 throughout the full range of tests which were conducted with supply temperatures ranging from 0°C – 40°C. The simulated results consistently overestimated the experimental results by between 12% - 15%. New empirical heat exchanger relationships were developed for the model bringing the simulated results within 5% of the experimental results for tests run at glycol flow rates of 77 and 154 kg/hr. These relationships were used to refine the model, and produce updated annual performance values in the TRNSYS simulation software. Updated results showed a 5% drop in the annual free energy ratio in Toronto from 57% to 52%, but further optimization of the system using the TRNSYS software package improved annual results up to 56%. For the purposes of the study, a solar assisted heat pump prototype was constructed and tested successfully within the laboratory environment. Results showed that the system has a strong market potential, especially in regions without a strong solar resource. Based on these results further research is recommended, continuing with a full year outdoor test using unglazed solar collectors. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-10-12 18:53:01.189

The development of precast concrete housing systems provides an opportunity to easily and inexpensively incorporate solar energy collection by casting collector tubes into the roof structure. A design is presented for a precast solar water heating system used to aid in meeting the space and domestic water heating loads of a single family residence. A three-dimensional transient collector model is developed to characterize the precast solar collector's performance throughout the day. The model describes the collector as a series of segments in the axial direction connected by a fluid flowing through an embedded tube. Each segment is represented by a two-dimensional solid model with top boundary conditions determined using a traditional flat plate solar collector model for convection and radiation from the collector cover plate. The precast collector is coupled to a series solar assisted heat pump system and used to meet the heating needs of the residence. The performance of the proposed system is compared to the performance of a typical air to air heat pump. The combined collector and heat pump model is solved using Matlab in conjunction with the finite element solver, Femlab. Using the system model, various non-dimensional design and operating parameters were analyzed to determine a set of near optimal design and operating values. The annual performance of the near optimal system was evaluated to determine the energy and cost savings for applications in Atlanta, GA and Chicago, IL. In addition, a life cycle cost study of the system was completed to determine the economic feasibility of the proposed system. The results of the annual study show that capturing solar energy using the precast collector and applying the energy through a solar assisted heat pump can reduce the electricity required for heating by more than 50% in regions with long heating seasons. The life cycle cost analysis shows that the energy savings justifies the increase in initial cost in locations with long heating seasons but that the system is not economically attractive in locations with shorter heating seasons. / Master of Science

The Swedish government has set a target of a 100% renewable electricity system by 2040. To reach this goal, many actions have to be undertaken. Electrification of buildings is one action to be undertaken as the residential sector accounts for a large share of greenhouse gas emissions, where the most energy efficient method is to use heat pumps. Ground Source Heat Pumps typically have the highest efficiency out of the different heat pumps. These types of heat pumps are most commonly used in single family houses, as multi-family houses often are located in highly densely areas. However, when adding hybrid PV/thermal collectors to ground source heat pump systems, studies have shown that the borehole drilling area can be reduced, which increases the potential for combined PV/thermal collectors and ground source heat pump systems in multi-family areas.  In this project, a time-efficient, flexible and user- friendly model was developed to increase the potential for designing combined PV/thermal collectors and ground source heat pump systems. The model is based on the research model by Sommerfeldt and Madani (2019), where the flexibility and time step of the model was investigated and adjusted. The finished model was verified to the model by Sommerfelt and Madani (2019). Overall, the results show that the new model gives similar results to the original model, despite all adjustments. The heaviest adjustments were made in the heat pump where the quantitative results show a mean bias error of -0.51 kWh and a total yearly difference of -5.18% for the compressor power. The corresponding values for the condenser heating rate are -1.05 kWh and -2.86%. The user is able to change boundary conditions such as location, PVT array, building size, and borehole field size. The model takes approximately 2 minutes to run for a 20 years simulation on a business grade desktop computer, which is a five-hour twenty minute reduction from the original research model and assumed to be an acceptable time range for a commercial applications. / Regeringen har satt ett mål om att nå ett 100% förnybart energisystem till 2040. För att nå målet måste många insatser göras. Bostadssektorn står för höga halter av växthusgasutsläpp och elektrifiering av sektorn är en lovande väg att gå. Värmepumpar tillhör de mer energieffektiva tillvägagångssätten, av vilka bergvärmepumpar oftast erhåller den högsta effektiviteten. Bergvärmepumpar är idag mestadels installerat i enfamiljshus där det finns utrymme för att borra borrhål. Flerfamiljshus finns ofta i tätbebyggda områden där ytan tillgänglig för borrhål är begränsad. Emellertid har studier har visat att kombinerade PVT och bergvärmesystem kan minska borrhålsytorna, vilket ökar möjligheten för dessa typ av system även till flerfamiljshus.  Detta projekt syftar till att utveckla en kommersiell modell för design av PVT och bergvärmesystem för att underlätta design av dessa system. Att modellen är kommersiell antyder på att den är användarvänlig, flexibel och tidseffektiv. Modellen är baserad på en forskningsmodell av Sommerfeldt och Madani (2019) men justerades för att möta kraven för en kommersiell modell. Den färdiga modellen jämfördes och verifierades med modellen av Sommerfeldt och Madani (2019). Övergripande visades resultat som är jämförbara med forskningsmodellen, trots alla justeringar. De största justeringarna gjordes i värmepumpen där de kvantitativa resultaten visar ett mean bias error på -0.51 kWh och en årlig skillnad på -5.18% för elbehovet i kompressorn. Motsvarande värden för värmeutbytet i kondensorn är -1.05 kWh och -2.86%. Användaren har möjlighet att ändra gränsvillkor så som geografisk plats, PVT system, byggnadsstorlek och storleken på borrhålsfältet. Den färdiga modellen tar cirka två minuter att köra för en 20-års simulering på en typisk arbetsdator, vilket motsvarar en minskning på 5 timmar och 20 minuter jämfört med originalmodellen. Detta kan anses vara inom tidsramen för kommersiella appliceringar.

In this thesis, performance of a heat pump aided by solar heating system with an evacuated tubular collector has been analyzed theoretically and experimentally. For this purpose, a domestic hot water heating system has been designed, constructed and tested. The evacuated tubular solar collector has been used to achieve higher collector efficiency in winter. The fraction of the solar energy utilized has been measured experimentally and estimated theoretically. Effects of various parameters have been investigated on the performance of the proposed system. A mathematical model was developed to investigate the effects of different environmental, design and operational parameters on the solar heating system. In order to compare the obtained theoretical results with experimental ones, an experimental study has been carried out. For that, a number of experiments have been made at the solar house of the Mechanical Engineering Department of METU. An air-to-air heat pump was integrated with an evacuated tubular solar water heater unit (closed water circulation) and the performance of it has been studied experimentally. As a result of the experimental study, the maximum value of the coefficient of performance of the solar assisted heat pump used in this study was obtained as 4.85. The second law efficiency of the system was between 4.8-27.4 %.