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Introduction

Pilot project on Design and Development of 106kWatt LiBr Absorption Cooling and Heating System with parabolic troughs



The increasing energy demand for air conditioning, refrigeration and heating is leading towards the renewable energy solutions. The energy supply difficulties, depletion of energy resources and extreme environmental harmful effects like global warming, depletion of ozone layer and climate change has refused to overcome the increase in the fast growing world energy demand on daily basis. The worldwide contribution towards the energy consumption from the building, of both residential and commercial has increased in the percentage between 20% and 40% in the developing countries, and this percentage is higher than other major sectors like transportation and industrial. There are many factors like increase in growth of population, increasing demand for building services and the human comfort level, energy consumption time in the building, which shows that energy demand will continue to grow in the future. This is the reason that there is a need to focus at the energy policy at regional, national and international level as a prime objective.

Heating and Cooling load in summer and winter seasons are continuously increasing burden on our national grid. This type of load is mainly required for our domestic and commercial buildings, which is around 50% of the total load. Solar power based cooling and heating systems are the best solution to overcome these problems, because Pakistan is enriched with solar energy.

Solar cooling systems can be categorized mainly in absorption systems, adsorption systems, desiccant systems and mechanical systems. Single effect water/ LiBr absorption chillers integrated with flat-plate or evacuated tube are commonly used. Coefficient of Performance (COP) for this type of cooling system ranges from 0.5 to 0.8 and temperature range is 75OC ? 95OC [1].

Power source that will be utilized is solar energy. Solar parabolic concentrators will be used to provide heat to Absorption Cooling and Heating System (ACAHS). Solar tracker will be designed to obtain maximum efficiency of solar system. Parabolic troughs are more reliable, durable and low cost than the other solar technologies. ACAHS is a vast field of study and extensive research has been conducted in this field. Research and literature on absorption cooling technology is very diverse and different designs with various material types can be observed. Most of ACAHS has been designed and operated through electricity, fuel and natural gas but use of solar energy can significantly reduce the cost. The following pictures provide a glimpse of how a parabolic trough looks like: