Household appliance integrated heat pump atmospheric water generator design

Due to the lack of clean water resources and the acceleration of the increase in world population, problems related to access to clean water have been emerged in various regions. According to the results of survey, it estimated that difficulties related to access to clean water would increase within 30 years. Therefore, the quest for alternative sources of clean water is one of the popular topics today. Increasing the energy efficiency of household goods and the reduction of water consumption are one of the most important issues. 20% of the water is consumed in various purposes through household products and recycling of gray water cannot be ensured. Reduction of water consumption in household goods is one of the critical factors in the prevention of clean water shortages that is expected to increase in the future. Atmospheric water generators are the systems that enable the condensation of moisture in the air by the physical methods. Atmospheric water generator can provide a source for potable water after the filtering processes on condensate. Condensation phenomenon can be encounter in many engineering problems. In order to conditioning of the ambient air in air conditioning systems and industrial dryers, open or closed loop applications have used. Moreover, liquid desiccants, solid desiccants and heat pump systems are the common technologies that have been used to extraction of water from humid air for generating portable water. The efficiency of AWG is highly related with the method of condensation and designing of system components. Efficient use of energy and water becomes the focus of both academic and industrial researches. Manufacturers of different areas reunited for the aim of producing less energy and consuming less water. On the account of this, experimental and numerical studies have carried out in this graduate thesis in order to design of house appliance integrated heat pump atmospheric water generator. This thesis study is composed of experimental and numerical for designing of heat pump components. Experimental studies on the benchmark, arranging of numerical solution model with ε-NTU method based heat exchanger solver "CoilDesigner" and determination of practicality have carried out. Determining the applicability of the numerical model, models have created and the numerical analyses have carried out in order to identify the model that providing the design criteria. Based on the relevant numerical analysis, appropriate design has been determined, produced and investigated experimentally. According to researches that are related to water resources and population growth, it is determined that there are several problems associated with access to clean water in various region and due to the physical factors, economical reasons and technological deficiencies it is estimated that worldwide water scarcity will be occurred. One of the main goal of the thesis is providing a renewable potable water source that could be an innovation solution to incoming water shortage. In order to determine the appropriate method of water production, various condensation techniques have examined and comparisons have carried out. Experimental studies have performed based on comfort condition that is specified in standards as 20oC-25oC ambient temperature and 40%-60% relative humidity. As a results of the researches based on desiccant, heat pump and pressure system; household appliance integrated water generation technology has determined. Desiccants are regarded as structures for absorbing water vapor in the air and have been used in dehumidification process. The process of moisture extraction with the dry desiccants is specified as "Adsorption" (Silica Gel, Zeolite) and with the liquid desiccants is specified as "Absorption" (Glycerol, LiCl, LiBr, CaCl2). The moisture extraction rate of absorption process is higher than adsorption and temperature of regeneration is lower than absorption process. Considering the necessity of regenerating system, regeneration temperature and the condensation requirement of regenerated water vapor; requirement of the various components and a complex system design could occur. Dew point temperature of moist air can be increase by the pressurizing process and condensation occurs at ambient temperature without having a cold surface. Review of the literature and experimental studies with a pressure vessel have carried out and due to the need for a plurality of components, the difficulty of evacuation of condensed water under pressure and the high power requirement for pressurization, it is concluded that the method is not feasible to generating water. Heat pump integrated systems have used through various fields for the purpose of heating, cooling and air conditioning. Being provided components easily, high efficiency, to demonstrate high efficiency in the specified environmental conditions and to have the technologically advanced components, heat pump systems are shown in today's popular technologies. Based on various design criterions, extraction of moisture in humid air with the heat pump is determined as the method that provides potable water to household appliances. For the purpose of the examination of AWG components and determinations design parameters, a comprehensive literature research has executed based on evaporator design. Dimensional parameters of evaporator, the structure of the coating and pre-cooled methods are determined as effective parameters on the efficiency of system. Dimensional parameters of evaporator are specified that provides an effective condensation process. For example, according to the results of various numerical and experimental studies it was determined that the fin spacing should be around 1,5mm. The effects of the coating on evaporator performance were investigated and it is concluded that super hydrophilic coating (3o-20o contact angle) provides a higher performance on evaporator and condensation process. Nevertheless, the applicability of super hydrophilic coating due to the limited life of the coating materials is a controversial issue today. Through direct evaporative and indirect evaporative pre-cooling methods the performance of evaporator could increased, however the installation and appropriate design of additional components are important topics that should examined. Benchmarking has carried out for the purpose of detailed examination of heat pump atmospheric water generator, components, operating conditions of the system, effective parameters through system. In the experimental results, it was seen that the evaporation temperature and the amount of water produced vary depending on the ambient conditions. Ambient temperature, ambient relative humidity, mass flow rate of air, the evaporator temperature and the compressor capacity is determined as effective parameters of the system. Experimental studies have performed with the referred working conditions of European Union EN 61121 standard that are 230 V mains voltage, 50 Hz mains frequency, 23oC ambient temperature and 55% relative humidity. As the result of experimental studies, 450 mL of water per hour has generated at the steady state operating conditions. Furthermore, according to literature research and technical studies for environments with a relative humidity less than 30% no water generation occurs. The average annual relative humidity distribution throughout the world and in Turkey were examined and water generation could be achieved in areas where water shortage. It is experimentally determined that there is no water generation because of the occurred ice formation through evaporator where evaporation temperature of refrigerant is less than 0oC (18oC ambient temperature and 30% relative humidity). The cooling capacity, the amount of condensed water vapor, the total area of the evaporator and power of the system is determined to be effective parameters on the efficiency. Based on these parameters, four different efficiency definitions have generated that are specified as GSO (ratio of cooling capacity per latent heat quantity), YSO (ratio of the cooling capacity per condensed water vapor per unit time), YEO (the ratio o energy required per condensed water vapor per unit time) and YAO (the ratio of the total heat transfer area of evaporator per condensed water vapor per unit time). In order to providing an approach before designing by the components that have used in experimental studies, a numerical model has created with the CoilDesigner 4.0 heat exchanger solver had developed by University of Maryland. In order to create a numerical examination model of evaporator, various correlations have used for dry and wet surface conditions, heat transfer coefficients, pressure losses, fin efficiency and porosity. Through experimental studies, numerical solution model and identification of efficiency definitions, determination of the system efficiency and investigation of methods to increase in efficiency have realized. According to the results of numerical study carried out for pre-cooling system, increase in efficiency could provided with a mechanical structure that placed before the evaporator. Requirement of the various components to precool method, continuously controlling the pre-cooling process and increase in the total volume of product; the pre-cooling method is not appropriate for the household appliance integrated heat pump water generator. In order to prevent from retention and accelerate the evacuation of accumulated water over fins, implementation of a mechanical force to evaporator has foreseen. Based on this foreseen, impact and vibration effects on the evaporator have investigated. As a result of experimental studies, quantity of the condensed water increased 12,9% owing to vibration applications and 20,7% owing to impact application. Although the increase the amount of water generation, due to the number of required components and the cost of system it has determined that methods which comprise mechanical force are not suitable for household appliance integrated heat pump atmospheric water generator. According to experimental and numerical studies through inlet airside flow rate, it was determined that the effect of air flow rate on the efficiency decreases at the steady state operating conditions. Moreover, as a result of comparisons between the numerical solution model with experimental studies, percentage changes of YSO is 4,63% and YAO is 4,13%. In that case, it has concluded that numerical solution method of CoilDesigner could be used as a tool for generating designs. Based on the design criterions, pre-designs have created for determining the appropriate evaporator model to providing the desired amount of water productivity. Evaporator that designed for integrated heat pump has examined with numerical analysis and experimental methods. According to comparison between numerical and experimental methods, it is determined that percentage changes for the model of four rows of tube evaporator YSO is 11,8% and YAO is 0,5%. Consequently, numerical model has created for the evaporator that provides the design criteria and as a result of experimental studies, it has determined that the credibility of the numerical solution method is reliable. Comparing the results of experimental studies which carried out to benchmark and integrated heat pump, it has detected that efficiency of integrated heat pump increase 10,1% for YSO, 25,3% for YEO and 44,7% for YAO. Sustainability, water and energy issues are the main motivations for this thesis study. In order to prevent or reduce water consumption in household appliances, it is intended to design the system that produces sufficient amount of water from air and the energy that required for the production of water from renewable sources. As a result of negotiations with the various firms, installation work has carried out in Çayirova Campus of Arçelik A.Ş. Installed power of system is 1000W and the average energy storage capacity is around 4kWh.