This master’s thesis pertains to heating practices of low-energy houses using a heat pump (example 1) and low-temperature condensing boiler (example 2). The first part of the work contains calculations of suggested building’s heat efficiency and of under-floor heating. The second part of the work includes estimates of seasonal heating factors for construction with a heat pump. Based on the comparison: both of these heating systems are recommended; the capacity of the warm water container is established; and safety elements are chosen. Furthermore, a system of regulation for warm water heating is determined, and a curve of equithermal regulation for heating is calculated. Both of the recommended heating possibilities include calculations of costs of supplies and manufacturing, as well as blueprints for construction.

Aujourd'hui, la pompe à chaleur (PAC) est largement utilisée pour les applications de chauffage du bâtiment en raison de ses bonnes performances énergétiques. Elle est même considérée comme une source d'énergie renouvelable et, selon la Directive Européenne 2009/28/CE, la part «renouvelable» de l'énergie produite doit être calculée à partir de la performance annuelle. Il est donc important d'être à même de mesurer cette dernière. Or, il n'existe pas, pour les PAC air/air, de méthode fiable et simple permettant de mesurer la performance chez le client pendant une saison.Dans ce contexte, la thèse propose deux méthodes in situ qui répondent à ce besoin. La première est basée sur des mesures non-intrusives des propriétés du fluide frigorigène. Elle utilise le bilan énergétique du compresseur pour déterminer le débit du fluide. La deuxième, fondée sur les mesures côté air, utilise un ensemble de capteurs à fil chaud afin de mesurer le débit et les températures d'air.La thèse développe également une méthode de mesure intrusive du fluide frigorigène, qui n'est pas adaptée aux conditions in situ mais sert de référence pour valider les deux méthodes in situ. Les résultats expérimentaux montrent que la méthode de référence est précise non seulement en conditions stabilisées mais également en fonctionnement dynamique (y compris lors des dégivrages).La validation des deux méthodes in situ a été réalisée par une campagne d'essais spécifique en laboratoire. Une suite intéressante de la thèse consistera à intégrer la méthode non intrusive côté frigorigène directement dans l'équipement de mesure et d'affichage de la PAC. / Today, heat pumps (HP) are widely used as heating systems in building thanks to their high energy efficiency. They are even considered as a source of renewable energy and, according to the EU Directive 2009/28/EC, the amount of renewable energy has to be calculated from the annual performance. Therefore, it is important to be able to measure the annual performance. However, concerning the air-to-air HP there is no reliable and simple method which allows measuring the performance in situ during at least a season.In this context, the thesis proposes two in situ methods that could fill this gap. The first one is based on non-intrusive measurements on refrigerant side. It uses a compressor energy balance to determine the flow rate. The second one, based on air measurements, uses a distribution of hot-wire sensors to determine the air flow rate and temperatures.The thesis also develops an intrusive refrigerant method, which is not necessarily adapted for in situ conditions but can be used as a reference to validate the in situ methods. The experimental results show that the reference method is accurate both in stationary conditions and in dynamic operations (including during defrosting period).The validation of the in situ methods was performed by a specific test campaign in laboratory. As a perspective, the thesis makes it possible to develop on-board measurement methods using non-intrusive refrigerant sensors, providing an opportunity for manufacturers to display the in situ performance in real time.

The UK government’s Carbon Plan-2011 aims for 80% carbon emission reduction by 2050, and the 2009 UK National Renewable Energy Action Plan has set a target of delivering 15% of total energy demand by renewable energy sources by 2020. Ground Source Heat Pump (GSHP) systems can play a critical role in reaching these goals within the building sector. Achieving such benefits relies on proper design, integration, installation, commissioning, and operation of these systems. This work seeks to provide evidence to improve the practices in design, installation and operations of large GSHP systems. This evidence has been based on collection and analysis of data from an operational large-scale GSHP system providing heating and cooling to a university building. The data set is of significance in that it is collected from a large-scale system incorporating fifty-six borehole heat exchangers and four heat pumps. The data has been collected at high frequency since the start of operation and for a period of three years. The borehole heat exchanger data is intended to form a reference data set for use by other workers in model validation studies. The ground thermal properties at the site have been estimated using a novel combination of numerical model and parameter estimation methods. The utility of the reference data set has been demonstrated through application in a validation study of a numerical borehole heat exchanger model. The system heat balances and power consumption data have firstly been analysed to derive a range of performance metrics such as Seasonal Performance Factors. Analysis has been carried out at the system and individual heat pump level. Annual performance has been found satisfactory overall. A series of analyses have been carried out to investigate the roles of circulating pump energy, control system operation and dynamic behaviour. Monitoring data from one of the heat pumps has also been analysed in further detail to make comparisons with manufacturer’s steady-state performance data and with consideration to variations in fluid properties. Some modest degradation from stated performance has been identified. The most significant operational factors accounting for degradation of overall system performance have been excessive pump energy demands and short cycling behaviour. Some faults in operation of the system during the monitoring period have also been identified. A series of recommendations are made as to ways to improve the design and operation of large-scale GSHP systems based on this evidence. These recommendations are chiefly concerned with better design for part-load operation, reduction in pump energy demands and more robust control systems.

An experimental study was carried out to evaluate the performance of pilot scale constructed wetlands for the treatment of domestic wastewater in Addis Ababa, Ethiopia. Three parallel sets of constructed wetlands; consisting of one Horizontal Flow (HF), one Vertical Flow (VF) and one hybrid of HF and VFconstructed in series were built in Addis Ababa. The wetland systems had identical wetland fill media and macrophytes but with different wastewater flow types. The total surface area of the wetland systems was 72 m2 /24 m2 for each/ and designed to treat 3.15 m3 of domestic wastewater per day. Triplicate grab samples were taken from the influent and effluents every 15 days for one year and analyzed within 24 hours. Temperature, pH, DO and EC were measured onsite and the nutrient content of macrophytes was determined twice during the monitoring period. During the first 12 months monitoring period, the average removal efficiencies of the HFCW, VFCW and hybrid CW were: BOD (89.1%, 92.2% and 93.4%), COD (80.6%, 82.1% and 84.0%), TSS (89.1, 83.8% and 84.7%), NH4 + (58.6%, 66.2% and 65.4%), NO3 - (64.0%, 71.5% and 73.5%), TN (49.1%, 54.9% and 58.7%), PO4 3- (45.4%, 50.3% and 48.4%), TP (58.0%, 51.7% and 54.4%) and FC (98.6%, 96.6% and 96.5%), respectively. The hybrid system showed relatively higher removal efficiencies for most pollutants. Again, the wetland systems showed relatively higher percent reduction during the dry seasons /from Dec - May/. The areal removal rate constants of BOD5, TN, PO4 3- and TP were higher than the literature values while the values of COD and TSS were lower compared to the literature values. Concerning the nutrient content of the wetland plant, the average TN contents of the below-ground and above-ground plant part were 1.56% and 2.27% for the HFCW, 1.75% and 2.74% for the VFCW and 1.80% and 2.63% for the hybrid system, respectively. Meanwhile, the average TP contents of the belowground and above-ground plant part were 0.139% and 0.064% for the HFCW, 0.167% and 0.067% for the VFCW and 0.115% and 0.065% for the hybrid systems, respectively. In general, the results showed that properly designed constructed wetland systems could be used as effective wastewater treatment method in Ethiopia. / Environmental Sciences / Ph. D. (Environmental Sciences)