This document presents the energy analysis and simulation of central solar heating plants with seasonal storage (CSHPSS) designed for covering a part of residential heat demand required for SpaceHeating (SH) and Domestic Hot Water (DHW) oriented to reduce the consumption of fossil fuels.The main objectives of this thesis are to simulate and analyse in POLYSUN software a defined systemof CHSPSS already built in TRNSYS, in order to compare the results of both programs and to analyse and simulate these systems in different cities of Spain. In carrying out the objectives, some limitations have been found. Ones of these are the limitations of POLYSUN program, which have forced to reduce the number of housings. The document starts with a revision of the state of art, in which it is shown the number of plants in Europe and specially, in Sweden and Spain observing the differences between them, for example, Spain has not any CSHPSS plant and Sweden was the first country of building one. In addition, in the theory section, it has been studied the main elements of these plants, such as different types of solar collectors and seasonal storages, and different simulation programs commercially available for the simulation and analysis of this type of plants. According to this, POLYSUN program is more intuitiveand user-friendly in some extent than TRNSYS, but its applications are more specific and more appropriate for small district heating systems. Steps followed for obtaining the analysed system and main characteristics of it have been explained.These steps have been used to analyse the results of POLYSUN and to compare results betweenTRNSYS and POLYSUN. According to the obtained results, it can be remarked that the results obtained from POLYSUN are coherent, with the exception of Space Heating demand, which is calculated by the program and has a very important difference between the calculated value and the Space Heating demand introduced by the user. When comparing with TRNSYS, it has been observed that POLYSUN‘s boilers have a high thermal losses and low efficiency and POLYSUN’s pumps have high energy consumption and thermal losses.

The study compared four different cooling systems and analyzed the competitiveness in those systems regarding electricity consumption, environmental impact and life cycle cost analysis. The assignment was given from the consultant company Ramböll who believed in these systems design as a solution to minimize the energy consumption in cooling systems. The purpose of the study was to facilitate the selection of cooling system by finding a key ratio for profitability in terms of energy consumption. This makes it easier to select one of these systems in project planning. A representative building model was built in the energy simulation program IDA ICE. From these result an energy profile was achieved.   The energy profile was then used in another simulation program called Polysun were detailed system regulations could be made. By programing the controllers to regulate the distribution in an efficient way the energy consumption was minimized and matches the building cooling demand. The simulation was done for one full year and the obtained total energy consumption for each system, it was then used to calculate the operational cost. The life cycle cost analysis is a tool that compare each system costs during its lifetime. A depth analysis was also done regarding the sensitivity of changes in the profitability for the systems, by applying different electrical price and cost of capital.   The study shows that the systems with different borehole storage solutions proves to be effective systems for covering the building cooling demand with a significant lower electricity consumption, compared to the system with a chiller. The different borehole storage systems also contribute to cover some parts of the heat demand, since the stored heat needs to be used in order to make the borehole storage functional. By analyzing the cooling systems in a comparative perspective, the most effective solution is identified from an economic and environmental point of view. The cooling system that only contained a borehole storage was the solution that distinguished the most regarding total electricity consumption and environmental impact. This system resulted in being the most profitable cooling system between the compared systems. The combined system with a borehole storage system and a heat pump solution was also proven to be an effective cooling system, additionally with an advantage of providing parts of the hot water demand in the building.

This thesis describes utilisation of test reference year for design and evaluation of solar thermal system. The evaluation was performed on a solar thermal system of a single-family house in Rapotice, Czechia. Long-term monitoring of the system as well as indoor and outdoor climate were performed there. Measured data were compared with test reference year and data in Meteonorm database. Selected boundary conditions of the solar thermal system were compared with numerical simulations in Polysun. The results of the comparison were statistically analysed. Results of the simulations utilizing test reference year were closer to the on-site measurements than dates from Meteonorm. Therefore it could be concluded that test reference year is the best database of climate data for design of solar thermal system in Czechia.

Energy usage deriving from human activities is increasing day by day acting against the quality of the environment and the sustainable use of natural resources. The major impact of these actions is reflected on the quality of daily life. In order to face the challenge of preserving an acceptable balance between human needs and environmental status, the combination of proper design and energy simulation of buildings is the key towards smarter and more sustainable solutions. Solutions that covers a respectable percentage of the current domestic energy needs without further environmental foot printing. In the scope of this project, an existing single-family house in Southern Greece (Heraklion, Crete) is modeled using Revit ® Architecture software and then is simulated with IES® VE (plug-in) in order to give the level of energy intensity. The energy model used is fully harmonized with the new rules set by the "National Regulation for Energy Performance of Buildings - (K.En.A.K)" as it was put in force from October 2010 and onwards, and fully complies with the European Standards (EN ISO) published for the various tasks of building`s thermal performance. The structure and contents presented in this report are in full compliance with the technical directives [31, 32, 33] published by the Technical Chamber of Greece, in favour of the complex task of "Energy Certification of Buildings". The most significant capabilities of sophisticated software tools, like Revit® Architecture, IES® VE, Polysun® and PVsyst®, in favour of sustainable building design and simulation are shown throughout the whole report. Moreover, their valuable contribution is highly acknowledged by the engineers encountered with the task of studying the energy performance of existing or newly constructed buildings in Greece and issuing, the mandatory by law, "Energy Performance Certificates".

The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.