scholarly journals Solar water heating systems for different buildings under a hot climate; parametric optimization and economic analysis

2018 ◽  
Vol 3 ◽  
pp. 3 ◽  
Author(s):  
Kheira Tabet Aoul ◽  
Ahmad Hasan ◽  
Hassan Riaz

Building applied solar thermal systems are considered by different stakeholders an attractive alternative to traditional space and water heating systems. However, their performance depends largely on climatic conditions, water heating needs and operational parameters which, in turn, offer opportunities for performance optimization. The present research attempts to provide architects with a design decision tool that integrates solar thermal collectors efficiently to meet hot water demand for various building types inclusive of residential, commercial and industrial in a hot climate. The analysis is conducted numerically through a thermal model developed and executed in TRNSYS and validated experimentally. The parameters investigated include the collector tilt angle, azimuth angle and collector inlet fluid flow rate. Finally, the collector aperture area required per building foot print area is determined. The research revealed that for a 1000 m2 footprint building area of schools, offices, residential, factories and hospitals would require respectively 8 m2, 10 m2, 14 m2, 24 m2 and 38 m2 of the static collector installed at 24° tilt angle with optimal water flow rate. Additional operational aspects of collector tracking, and solar radiation concentration were investigated and further reduce the required collector area. A simple payback period analysis reveals a return on investment of 2 years applying subsidized tariff rates under the climatic conditions of, or similar to Dubai, in the United Arab Emirates.

2018 ◽  
Vol 8 (10) ◽  
pp. 1973 ◽  
Author(s):  
Adnan Ploskić ◽  
Qian Wang ◽  
Sasan Sadrizadeh

The aim of this study was to map the parameters that have the greatest impact on the environmental impact of heating systems usually used in Nordic single-family dwellings. The study focused on mapping the technical requirements for efficient operation of heating systems in a broader context. The results suggest that the ability of a heating system to be operated with a low-temperature water supply depends to a large extent on the heating demand of a building. It was shown that an increase in the water flow rate in hydronic circuits would significantly increase the thermal efficiency from analyzed heating systems. This increase would not increase the pumping power need, nor would it create noise problems in distribution network if the distribution pipes and thermostatic valves were properly selected. However, this increase in water flow rate improved the efficiency of considered closed-loop heat pump. It was further shown that the efficiency of the heat pump could be additionally improved by halving the energy needs for the domestic hot-water and circulators. The main conclusion from this study is that exergy usage, CO2 emission and thereby environmental impact are significantly lower for heating systems that are operated with small temperature drops.


2015 ◽  
Vol 813-814 ◽  
pp. 700-706 ◽  
Author(s):  
R. Geetha ◽  
M.M. Vijayalakshmi ◽  
E. Natarajan

The PV/T hybrid system is a combined system consisting of PV panel behind which heat exchanger with fins are embedded. The PV/T system consists of PV panels with a battery bank, inverter etc., and the thermal system consists of a hot water storage tank, pump and differential thermostats. In the present work, the modeling and simulation of a Solar Photovoltaic/Thermal (PV/T) hybrid system is carried out for 5 kWp using TRNSYS for electrical energy and thermal energy for domestic hot water applications. The prominent parameters used for determining the electrical efficiency, thermal efficiency, overall thermal efficiency, electrical thermal efficiency and exergy efficiency are the solar radiation, voltage, current, ambient temperature, mass flow rate of water, area of the PV module etc. The simulated results of the Solar PV/T hybrid system are analyzed for the optimum water flow rate of 25 kg/hr. The electrical efficiency, thermal efficiency, overall thermal efficiency, equivalent thermal efficiency, exergy efficiency are found to be 10%, 34%, 60%, 35% and 13% respectively. The average tank temperature is found to be 50°C.


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