Ground source heat pumps (GSHPs) offer an efficient method for cooling and heating buildings, reducing energy usage and operating cost. In hot, arid regions such as Texas and the southwest United States, building load imbalance towards cooling causes design and performance challenges to GSHP systems in residential and commercial building applications. An integrated building load and GSHP model is developed in this thesis to test approaches to reduce GSHP cost, to properly size ground heat exchanger (GHEX) installations and to offer methods to improve GSHP performance in commercial buildings. The integrated model is comprised of a three-story office building, heat pumps, air handling system and a GHEX. These component models were integrated in the Matlab® Simulink® modeling environment, which allows for easy model modification and expansion. The building-load model was developed in HAMBASE, which simulates the thermal and hygric response of each zone in the building to external weather and internal loads. The building-load model was validated using the ASHRAE 140-2007 Standard Method of Test and with results from EnergyPlus. The heat pump model was developed as a performance map, based on data commonly provided by heat pump manufacturers. This approach allows for easy expansion of the number and type of heat pump models supported. The GHEX model was developed at Oklahoma State University and is based on Eskilson’s g-function model of vertical borehole operation. The GHEX model accurately represents the interaction between boreholes and the ground temperature response over short and long time-intervals. The GHEX model uses GLHEPRO files for parameter inputs. Long time-interval simulations of the integrated model are provided to assess the sensitivity of the GSHP system to various model parameters. These studies show that: small changes in the total GHEX length reduce system cost with minimal impact on performance; increased borehole spacing improves system performance with no additional cost; supplemental heat rejection reduces installation costs and improves system performance; industry-recommended design cutoff temperatures properly size the GHEX system; and, while cooling is the greatest contributor to operating cost in the southwest and southcentral United States, heating is the limiting design case for GHEX sizing. / text

Mr Wayne Tobeck, Director of Southrim Group (SRG), sponsored this 2013 MEM Project titled; A Technical and Economic Feasibility Study for the Integration of GSHP Technology in the Christchurch Rebuild. Following the recent Christchurch earthquakes, a significant amount of land has become too unstable to support traditional building foundations. This creates an opportunity to implement new and unique foundation designs previously unconsidered due to high costs compared to traditional methods. One such design proposes that an Injection Micro-Piling technique could be used. This can also be coupled with HVAC technology to create a Ground Source Heat Pump (GSHP) arrangement in both new buildings and as retrofits for building requiring foundation repair. The purpose of this study was to complete a feasibility study on the merits of SRG pursuing this proposed product. A significant market for such a product was found to exist, while the product was also found to be technically and legally feasible. However, the proposed product was found to not be economically feasible with respect to Air Source Heat Pumps due to the significantly higher capital and installation costs required. Further analysis suggests GSHPs may become more economically attractive in operating temperatures lower than -9oC, though the existence of markets with this climate in NZ has not been studied. It is therefore suggested that SRG do not proceed with plans to develop a GSHP coupled foundation solution for the Christchurch rebuild.

In this research paper, review of world geothermal energy production and their capacity is shown. Here, a research is conducted to know the potential and possibility of geothermal energy in India. All the geothermal province with their geographical locations are shown and a brief calculation is conducted in order to show the potential of the particular province. As India is having the low temperature geothermal fields, binary geothermal plants are used for this analysis and results are calculated by using R134a as a working fluid at different temperatures. The results are sufficient to prove the potential of geothermal energy in India.  Importance of Ground Source Heat Pump (GSHP) and power savings by its contribution over traditional heating and cooling methods is shown statistically. 9 different states of India are divided by their climatic condition, severe winter and moderate winter to calculate the heat demand in those states. Also, for the cold demands these states are considered to be same as per the climatic situation in summer. Then, comparison is done between GSHP and the traditional heating and cooling systems. The result shows the drastic power saving by using GSHP for space heating as well as cooling, over electric heater and air conditioner respectively.

<p>2008-05-26</p><p>Bedrock heat as an energy source</p><p>The sun has warmed up the bedrock and this heat can be used for warming up houses. Approximately 100 – 200 meters down in the bedrock the temperature of the heat is stable. This is a source of energy that can be used by installing a heat pump system. The ground source heat pumps are low maintenance and can last for many years. There is also a pollution risk for the groundwater and therefore the wells in the area. Before the ground source heat pump can be installed the municipality need to give permission, according to the environmental code. To install the system without permission is a crime against the environmental code. A requirement when applying for permission to install the heat pump system is to get the neighbours to agree with the place for the bore hole. The neighbour can appeal against the environmental and health authorities’ decision to give permission to install the ground source heat pump system. However there needs to be more research done regarding the environmental effects that may occur in the future, if the ground source heatpump system continues to increase as rapidly as today.</p>

2008-05-26 Bedrock heat as an energy source The sun has warmed up the bedrock and this heat can be used for warming up houses. Approximately 100 – 200 meters down in the bedrock the temperature of the heat is stable. This is a source of energy that can be used by installing a heat pump system. The ground source heat pumps are low maintenance and can last for many years. There is also a pollution risk for the groundwater and therefore the wells in the area. Before the ground source heat pump can be installed the municipality need to give permission, according to the environmental code. To install the system without permission is a crime against the environmental code. A requirement when applying for permission to install the heat pump system is to get the neighbours to agree with the place for the bore hole. The neighbour can appeal against the environmental and health authorities’ decision to give permission to install the ground source heat pump system. However there needs to be more research done regarding the environmental effects that may occur in the future, if the ground source heatpump system continues to increase as rapidly as today.

This master thesis presents a new technological combination of two environmentally friendly sources of energy in order to provide DHW, and space heating. Solar energy is used for space heating, and DHW production using PV modules which supply direct current directly to electrical heating elements inside a water storage tank. On the other hand a GSHP system as another source of renewable energy provides heat in the water storage tank of the system in order to provide DHW and space heating. These two sources of renewable energy have been combined in this case-study in order to obtain a more efficient system, which will reduce the amount of electricity consumed by the GSHP system.The key aim of this study is to make simulations, and calculations of the amount ofelectrical energy that can be expected to be produced by a certain amount of PV modules that are already assembled on a house in Vantaa, southern Finland. This energy is then intended to be used as a complement to produce hot water in the heating system of the house beside the original GSHP system. Thus the amount of electrical energy purchased from the grid should be reduced and the compressor in the GSHP would need fewer starts which would reduce the heating cost of the GSHP system for space heating and providing hot water.The produced energy by the PV arrays in three different circuits will be charged directly to three electrical heating elements in the water storage tank of the existing system to satisfy the demand of the heating elements. The excess energy can be used to heat the water in the water storage tank to some extent which leads to a reduction of electricity consumption by the different components of the GSHP system.To increase the efficiency of the existing hybrid system, optimization of different PV configurations have been accomplished, and the results are compared. Optimization of the arrays in southern and western walls shows a DC power increase of 298 kWh/year compared with the existing PV configurations. Comparing the results from the optimization of the arrays on the western roof if the intention is to feed AC power to the components of the GSHP system shows a yearly AC power production of 1,646 kWh.This is with the consideration of no overproduction by the PV modules during the summer months. This means the optimized PV systems will be able to cover a larger part of summer demand compared with the existing system.

Ground source heat pumps (GSHP) have the ability to significantly reduce the energy required to heat and cool buildings. Historically, deployment of GSHP's in the cooling-dominated Texas and Southwest region has been significantly less than in other regions of the United States. The long term technical and economic viability of GSHPs in arid regions such as Texas has been questioned due to failures of ground loop heat pump systems by early adopters. A proposed solution is to include a supplemental heat rejection (SHR) device to help offset the unbalanced ground loads. An integrated building load-ground source heat pump model is developed in this thesis and is designed to be a test bed for potential SHR devices. The model consists of discrete component models that can be mixed and matched to represent various types of buildings and ground source heat pumps. One of the unique features of the integrated model is the use of the Simulink/Matlab environment. This environment allows the user to develop component models that take advantage of the built-in functionality of Matlab and Simulink. Another unique feature is the full coupling of the building load, heat pump, and ground loop at every time step. The building load, heat pump, and ground loop models were chosen to allow for short time step simulations, which allows for a range of dynamic response times to be modeled and for different heat pump/SHR control methods to be explored. The integrated model can be used on any computer that has the Matlab and Simulink software. The building load model used, called HAMBASE, can model both residential and commercial buildings. HAMBASE was validated using the ASHRAE 140-2007 standard. The heat pump model uses readily available data provided by GSHP manufacturers to accurately model operation across a wide range of input conditions. The vertical borehole ground loop model, developed at Oklahoma State University, is based on Eskillson's g-function model, but included a one-dimensional numerical model to calculate the short term thermal response of the borehole and ground. The ground loop model utilizes GLHEPRO, a ground loop sizing and simulation tool, to create the required parameter files. Using the integrated building load-ground source heat pump model, a model of a single family house with a ground source heat pump was developed. The house model was validated by the results from eQuest and GELHPRO. A series of sensitivity studies were completed to determine dominant factors affecting the use of GSHPs in Texas and the Southwest regions of the United States. The results show that the life of a vertical borehole can be significantly extended/cut short if the ground parameters are properly/not properly designed prior to ground loop sizing. / text

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 177-192) Also available in print.

Since the building construction area is accounted for high share of energy usage (36 %) in Europe, there is high demand to pay attention to this area accurately. Sweden which is one of the pioneer countries in terms of building energy efficiency plans to reduce this value to 50 % by 2050. To reduce this value there is a need to define a mandatory guideline for builders by the government. So national board of housing, building and planning (Boverket) were given responsibility to define these regulations for builders and house owners. Parallel with that Swedish green building council developed a certification considering the buildin g’s energy demand, indoor air climate and environmental impact of building called Miljöbyggnad. While all the existing and new buildings following Boverket’s regulations meet this certification’s lowest limitations, some ambitious builders tend to fulfil its highest level of limitations called Gold level. This study aimed to design a house in the area of Smedjebacken to meet Miljö byggnad’s gold house’s energy category requirements. To meet the mentioned requirements several parametric studies regarding insulation thickness, windows assembly, heating and ventilation system are done via simulation software called TRNSYS. The result of testing several models show that although windows assembly does not affect this building ’s energy demand very much, other parameters such as insulation ’s thickness and type of heating system have a key role. In addition, a parametric study regarding the impact of thermal mass on the building energy demand is performed. The result shows that the effect of removed massive wood is compensated by replaced additional mineral wool insulation. In conclusion it is concluded that a single family house located in a cold climate like Smedjebacken using district heating cannot meet Miljöbyggnad’s gold level criteria without help of heat recovery ventilation. Furthermore, building with ground source heat pump as its heating system can meet Miljöbyggnad’s principals easier than those having district heating. In this case building with 200 mm insulation thickness even with exhaust air ventilation meets certification principals easily.

[EN] In a context of global warming concern and global energy policies, in which heating and cooling systems in buildings account for a significant amount of the global energy consumption, ground source heat pump (GSHP) systems are widely considered as being among the most efficient and comfortable heating and cooling renewable technologies currently available. Nevertheless, both an optimal design of components and an optimal operation of the system as a whole become crucial so that these systems can have a significant contribution to the attenuation of the global energy problem. The overall objective of this PhD dissertation is to perform the control and energy optimization of an experimental GSHP system installed at the Universitat Politècnica de València, making the control system adaptive to the thermal demand of the building and to the climate conditions. For that purpose, different control strategies are proposed, described, developed, implemented and tested in the system. The optimization of any system requires a comprehensive study of its behaviour, by means of a thorough analysis of all the variables and parameters implied on its performance. Therefore, the first step is to analyse the short-term performance of the system, but also the long-term performance based on the experimental data collected at the installation. Second and prior to developing any optimization strategies, it is important to analyse the optimal configuration of the system according to the objectives targeted. This objective includes the study of the best location for the temperature control sensor and the buffer tank, as well as an adequate size for this buffer tank. Finally, once the behaviour of the system has been fully understood, the components of the system are the most efficient according to the possibilities of the research work and they have been connected adequately, the final objective is to develop control and optimization strategies which optimize the operation of the experimental GSHP system. These strategies target the control of the heat pump compressor, but also and more importantly, the energy optimization of the complete system. The focus is not in optimizing the performance of each individual component, but in optimizing the energy performance of the system working as a whole. In this direction, a first approach which combined a temperature compensation strategy and the variation of the frequency of the water circulation pumps, and hence the flow rate, as a function of the thermal load of the building, was first attempted. The application of this first approach resulted in significant energy savings, but also in a lack of user comfort in some of the offices under extreme weather conditions during summer. Consequently, the control and optimization methodology has been upgraded in a global algorithm (which is the final result of this PhD thesis) which couples both strategies in order to ensure the user comfort while keeping significant energy savings. In brief, this PhD work provides a comprehensive experimental study for the energy optimization of a GSHP system for both cooling and heating operation. Experimental results for a one-year operation period demonstrate important energy savings when compared to the standard control operation, up to 35% in the summer season and 53% in the winter season, while keeping the user comfort. / [ES] En un contexto de creciente preocupación por el calentamiento global y de políticas energéticas internacionales, en el cual los sistemas de climatización en edificios representan una parte importante del consumo energético global, los sistemas de bomba de calor geotérmica están ampliamente considerados como una de las tecnologias de climatización de espacios más eficientes disponibles en la actualidad. Sin embargo, tanto un buen diseño de los componentes como una óptima operación del sistema son de vital importancia para que estos sistemas puedan contribuir de manera significativa a atenuar el problema energético global. El objetivo general de esta tesis doctoral es el control y la optimización energética de una instalación experimental de bomba de calor geotérmica construida en la Universitat Politècnica de València, haciendo que el sistema de control se adapte a la demanda térmica del edificio y a las condiciones climatológicas. Para ello, se proponen diferentes estrategias de control, las cuáles son descritas, desarrolladas, implementadas y evaluadas a lo largo de este trabajo de investigación. La optimización de cualquier sistema requiere un amplio estudio de su comportamiento, analizando concienzudamente todas las variables y parámetros implicados en su funcionamiento. Por tanto, el primer paso llevado a cabo es el análisis de los días típicos de funcionamiento de la instalación, pero también su comportamiento a más largo plazo, a partir de los datos experimentales recogidos. En segundo lugar, y como paso previo al desarrollo de las estrategias de optimización, es importante analizar la configuración óptima del sistema de acuerdo con los objetivos perseguidos. Este objetivo incluye el estudio de la posición del sensor de temperatura empleado para el control y del depósito de inercia, así como el dimensionamiento adecuado de este depósito. Finalmente, una vez se ha analizado en profundidad el funcionamiento del sistema, los componentes del mismo son lo más eficientes posible, y éstos han sido conectados de manera adecuada, el objetivo final es el desarrollo de estrategias de control y optimización energética que optimicen la operación de la instalación experimental de bomba de calor geotérmica. Estas estrategias se dirigen principalmente a la optimización del sistema completo. El objetivo no es optimizar el funcionamiento de cada componente de manera individual, sino optimizar el comportamiento energético del sistema trabajando como un todo. En este sentido, se desarrolló una primera metodología que combinaba la compensación de la temperatura de consigna de la bomba de calor en función de la temperatura ambiente exterior, y la variación de la frecuencia de las bombas de circulación (y por tanto el caudal de agua) en función de la carga térmica del edificio. La aplicación de esta primera estrategia resultó en una importante mejora del rendimiento energético, pero también en la pérdida de confort en algunas de las oficinas climatizadas cuando las condiciones climatológicas eran extremas durante el verano. En consecuencia, la metodología de control y optimización desarrollada fue mejorada dando como resultado un algoritmo global de optimización energética (que es el resultado final de esta tesis), el cual acopla ambas estrategias anteriores de manera que se cumpla el confort del usuario y se mantenga un ahorro de energía significativo. En resumen, esta tesis doctoral proporciona un estudio experimental exhaustivo de la optimización energética de un sistema de bomba de calor geotérmica para la climatización de un edificio de oficinas. Los resultados experimentales para un año completo de funcionamiento del sistema muestran un ahorro de energía significativo en comparación con el modo de control de referencia, hasta un 35% en modo refrigeración y un 53% en modo calefacción, a la vez que se mantiene el confort de los usuarios. / [CAT] En un context de creixent preocupació per l'escalfament global i de polítiques energètiques internacionals, en el qual els sistemes de climatització en edificis representen una part important del consum energètic global, els sistemes de bomba de calor geotèrmica estan amplament considerats com una de les tecnologies de climatització més eficients disponibles en la actualitat pel que fa a la climatització d'espais. No obstant això, tant un bon disseny dels components com una operació òptima del sistema són de vital importància per tal que aquests sistemes puguen contribuir de manera significativa a atenuar el problema energètic global. L'objectiu general d'aquesta tesi doctoral és el control i l'optimització energètica d'una instal·lació experimental de bomba de calor geotèrmica construïda a la Universitat Politècnica de València, fent que el sistema de control s'adapte a la demanda tèrmica de l'edifici i a les condicions climatològiques. Amb aquest objectiu, es proposen diferents estratègies de control, les quals són descrites, desenvolupades, implementades i avaluades al llarg d'aquest treball d'investigació. L'optimització de qualsevol sistema requereix un ampli estudi del seu comportament, analitzant conscienciosament totes les variables i paràmetres implicats en el seu funcionament. Per tant, el primer pas duit a terme és l'anàlisi dels dies típics de funcionament de la instal·lació, però també el seu comportament a més llarg termini, a partir de les dades experimentals recollides. En segon lloc, i com pas previ al desenvolupament de les estratègies d'optimització, és important analitzar la configuració òptima del sistema d'acord als objectius perseguits. Aquest objectiu inclou l'estudi de la posició del sensor de temperatura emprat pel control i del dipòsit d'inèrcia, així com el correcte dimensionament d'aquest dipòsit. Finalment, una vegada s'ha analitzat en profunditat el funcionament del sistema, els components d'aquest són el més eficients possible, i han sigut connectats de manera adequada, l'objectiu final és el desenvolupament d'estratègies de control i optimització energètica les quals optimitzen l'operació de la instal·lació experimental de bomba de calor geotèrmica. Aquestes estratègies es dirigeixen principalment a l'optimització del sistema complet. L'objectiu no és optimitzar el funcionament de cada component de manera aïllada, sinó més bé optimitzar el comportament energètic del sistema treballant com un tot. En aquest sentit, es va desenvolupar una primera metodologia que combinava la compensació de la temperatura de consigna de la bomba de calor en funció de la temperatura ambient exterior, i la variació de la freqüència de les bombes de circulació (i per tant del cabdal d'aigua) en funció de la càrrega tèrmica de l'edifici. L'aplicació d'aquest primer apropament va resultar en una important millora del rendiment energètic, però també en la pèrdua de confort en algunes de les oficines climatitzades quan les condicions climatològiques eren extremes durant l'estiu. En conseqüència, la metodologia de control i optimització desenvolupada va ser millorada resultant en un algoritme global d'optimització energètica (resultat principal d'aquesta tesi), el qual acobla ambdues estratègies anteriors de manera que es complisca el confort de l'usuari i es mantinga un important estalvi d'energia. En resum, aquesta tesi doctoral proporciona un estudi experimental exhaustiu de l'optimit\-zació energètica d'un sistema de bomba de calor geotèrmica per la climatització d'un edifici d'oficines. Els resultats experimentals per un any complet de funcionament del sistema mostren un estalvi d'energia significatiu en comparació amb el mode de control de referencia, fins un 35% en mode refrigeració i un 53% en mode calefacció, a la vegada que es manté el confort dels usuaris. / Cervera Vázquez, J. (2016). Control and energy optimization of ground source heat pump systems for heating and cooling in buildings [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/66748 / TESIS