Thermodynamic analysis of lithium bromide absorption chiller driven by geothermal energy
The use of geothermal energy as a heat source to drive vapor absorption chillers has been receiving more interest. Geothermal energy is sustainable, economically viable and environmentally friendly. Absorption chillers powered by geothermal energy are still in their development phase. In this work, a lithium bromide absorption chiller operated with a geothermal heat source will be thermodynamically analyzed. The focus will be on the solution heat exchanger performance, in particular, the effect of geothermal heat source fluid temperature as well as mass flow rate on the absorption chiller coefficient of performance (COP). The effectiveness of the solution heat exchanger will be also studied and evaluated. Preliminary results showed that as the pressure in geothermal water vapor separator increased from 0.23 to 0.45 MPa, the absorption chiller cooling load increased by 28% while the COP decreased by only less than 1.4% at the same condenser pressure.
Thermodynamic analysis of geothermal series flow double-efffect water/LiBr absorption chiller
In this work, a thermodynamic analysis of a double effect water/LiBr absorption chiller of series configuration powered geothermal energy is presented. The geothermal energy is used to drive the desorber of the absorption chiller. This geothermal energy is obtained from the geofluid leaving an existing geothermal power plant before it is reinjected back to the ground. The effects of geofluid temperature, geofluid mass flow rate, chilled water temperature, condenser inlet temperature as well as the heat exchangers sizes are investigated to find out the performance of the chiller from coefficient of performance and cooling load points of view. This is done by using the mass flow rate and energy balances of each component of the absorption chiller combined with an Engineering Equation Solver software. The results show that the coefficient of performance and cooling load can reach about 1.32 and 475 kW, respectively under some operating conditions.
Solar assisted air conditioning of buildings – an overview
Abstract Goal of this contribution is to draw a picture about some general issues for using solar thermal energy for air conditioning of buildings. The following topics are covered: – A basic analysis of the thermodynamic limits for the use of heat cooling in combination with solar thermal energy is drawn; thereby fundamental insights about control needs for solar thermal driven cooling are obtained. – A short overview about the state-of-the-art of available technologies, such as closed thermal driven cooling cycles (e.g., absorption, adsorption) and open cooling cycles (e.g., desiccant employing either solid or liquid sorbents) is given and needs and perspectives for future developments are described. – The state-of-the-art of application of solar assisted air-conditioning in Europe is given and some example installations are presented. – An overview about new developments of open and closed heat driven cooling cycles for application in combination with solar thermal collectors is given and some of these new systems are outlined more in detail.