Applied Mechanics and Materials Vol. 315 (2013) pp 330-333 © (2013) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMM.315.330
Energy Savings and CO2 Reduction through Solar Water Heater Technology in Sindh Pakistan Mujeeb Iqbal Soomro1,a, Rizwan Ahmed Memon1,b and Khanji Harijan1,c 1
Department of Mechanical Engineering, Mehran University of Engineering and Technology, Jamshoro a
[email protected],
[email protected],
[email protected]
Keywords: Solar Energy, Water heating, RETScreen, Energy savings
Abstract. Pakistan suffers worst energy crises due to unavailability of primary energy sources. One of the solutions to energy problems of Pakistan lies in utilization of renewable energy sources like solar energy. One of the possible uses of solar energy is in the form of water eating. This work explored the availability of solar energy in the Sindh province of Pakistan. Moreover potential fuel savings and reduction in CO2 emission due to the use of solar water heating system is also evaluated. The RETScreen software was used for evaluation of fuel savings and CO2 emission reduction from a solar water heating system. Results show that the annual natural gas supplied to an average household in the three main cities of Sindh i.e., Karachi, Hyderabad and Sukkur could be reduced by 513.5, 409 and 543.5 m3, respectively. Annual reductions in emissions of CO2 for Karachi, Hyderabad and Sukkur were estimated to be 1, 0.8 and 1 tCO2 respectively. It is concluded that the utilization of solar energy for water heating in domestic sector of Sindh Pakistan could save fuel fossil and reduce environmental pollutants that in-turn may help mitigate energy crises in the country. Introduction Pakistan is suffering from regular power outages throughout the country. The primary sources of energy in Pakistan are oil, gas, coal, hydro and nuclear. With increasing demand of energy the need for primary energy sources is on the rise. The primary energy supply was 58.1 million TOEs in 2005-06 and increased to become 64.5 million TOEs in year 2010-11. Among all primary energy sources oil and gas have the highest share in consumption [1]. Indigenous sources of oil and gas are limited. With the current rate of production, the present recoverable indigenous conventional energy resources such as gas and oil will be exhausted in 21 and 13 years respectively [2]. Another issue with the use of fossil fuels is Pollution. Most gaseous pollutants released in the atmosphere are sulfur dioxide, carbon monoxide, carbon dioxide and chlorofluorocarbons (CFCs) [3]. By Sector wise consumption, the domestic sector is the third highest consumer of gas after power and industry sector. In Domestic sector, the consumption of gas is high as compare to all other sources. The prices of natural gas in domestic sector are also increasing sharply since 2007 [1]. In Domestic sector of Pakistan, natural gas is consumed for cooking and domestic water heating. Replacing conventional water heaters with solar water heating system would reduce overall energy consumption of the country and mitigate environmental pollution [4]. Solar Water Heating Technologies Solar energy collector is used to capture solar radiation emitted from the sun. Solar radiation is absorbed by the absorber plate and the heat energy is transferred either to the service water (open loop) or to some heat transferring fluid (close loop). Mainly solar water heating system is classified as Active and Passive solar water heating. In Active solar water heating system the circulation is forced i.e., with pumps, whereas in passive solar water heating system the circulation is natural i.e. thermosyphon system. Although there are many types of solar energy collectors, Selection is made on the required hot water demand per day, hot water temperature and season of use. Mostly used solar energy collectors are unglazed solar energy collector, glazed solar energy collector and All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 182.182.79.212, Mehran University of Engineering and Technology, Jamshoro, Jamshoro, Pakistan-07/04/13,18:06:20)
Applied Mechanics and Materials Vol. 315
331
evacuated tube solar energy collector [6]. Unglazed solar energy collectors don’t include a selective coating and insulation. These collectors are cheap, wind sensitive but less efficient. Whereas glazed and evacuated tube solar energy collectors include a selective coating and insulation. They are less wind sensitive (less thermal losses) and more efficient. Evacuated tube solar energy collectors are more expensive and efficient glazed solar energy collectors [7]. Solar water heating technologies are widely used in the countries where there is good potential of solar energy. In Asia, countries like China, Japan and India are on the top in using solar water heating. China has the highest share in the installation of solar water heating system Altogether 64% of the world’s solar water heating system were installed in china in 2009. Other countries like Turkey, Germany, Japan follows China in this regard; however, the share is less as compared to China [8]. Although the potential of solar energy in Pakistan is huge but the share of Pakistan in using solar water heating is negligible. Steps should be taken to create awareness and utilize this technology for water heating. Demand of Solar Energy Among renewable energy sources solar energy is freely available and environmental friendly. Pakistan is in the sun belt and can take advantage of the immense radiation available in the form of solar energy. However, this energy source is widely distributed and abundantly available in the country as shown in Fig. 1. The average daily insolation amounts to approximately 5–7 kWh/m2/day [5]. In Sindh Province the potential of solar energy is high in particular in the upper regions. Selected Regions and basic Parameters To estimate the potential benefits of solar water heating system, simulations were carried out in RET Screen software for heating water using solar radiation available in three main cities of Sindh Province. The selected cities for the investigation were Karachi, Hyderabad and Sukkur. The number of persons per household varies as such number of persons in an average house in Karachi and Sukkur were taken as seven whereas numbers of persons per household in Hyderabad were six. The passive evacuated solar water heating system is selected for evaluation and circulation was considered as natural (thermosyphon system). The basic parameters used to carry out simulations are enlisted in Table 1.
Fig. 1. Solar radiation map of Pakistan [5]
332
Mechanical & Manufacturing Engineering
Table 1. Basic parameters [9-11] Parameter
Value
Number of persons per house for Karachi and Sukkur Number of persons per house for Hyderabad
07 06
Occupancy rate (%) Daily hot water usage estimate (L/day) Hot water temperature (◦C) Operating days per week Solar water heater type Gross area per solar collector (m2) Aperture area per solar collector (m2) Fr (tau alpha) coefficient Fr UL coefficient Number of collectors Capacity (kW) Initial cost (USD) (Conversion factor 1USD=92.8 rupees, Dated 28th May 2012) Miscellaneous losses Storage capacity per square meter (L/m2) Conventional fuel type Seasonable efficacy (%) Natural gas rate ($/m3) Inflation rate (%) Project life (years)
90 380 50 7 Evacuated 2.96 2.78 0.50 2.00 1 3.25 540 3% 80 Natural gas 50% 0.06555 11% 25
Results and Discussions Based on the 25 years life of the project, the simulated results obtained for the simple and equity payback periods for Hyderabad are quite higher as compared to Karachi and Sukkur. Therefore, apparently the project will be more attractive for the cities of Karachi and Sukkur. It shows that the higher the number of occupants higher would be the annual fuel savings and annual CO2 reduction. Since Sukkur exists in the upper region of Sindh, the solar radiation is higher in Sukkur as compared to Karachi and Hyderabad. Therefore, the simple payback time is the least for Sukkur. Table 2. Results obtained from analysis
Karachi Hyderabad Sukkur
Simple payback (yr)
Equity payback (yr)
Annual Fuel Savings (m3)
Annual CO2 reduction (t CO2)
Equivalent in oil barrels
11.3 14.2 9.3
9.7 11.9 10.7
513.5 409.2 543.5
1 0.8 1
2.2 1.8 2.4
By installing solar water heating system, reduction in the use of natural gas per annum for a household in Karachi, Hyderabad and Sukkur comes out to be 513.5, 409.2 and 543.5 m3 respectively. Annual reductions in emissions of CO2 for Karachi, Hyderabad and Sukkur are estimated as 1, 0.8 and 1 tCO2 respectively. This reduction in the use of natural gas and in CO2 looks small for one house but it may become very important when thousands of houses are under consideration.
Applied Mechanics and Materials Vol. 315
333
Conclusion Solar water heating system is a mature technology and as Pakistan has good potential of solar energy so the utilization of this technology could be a good step to overcome present energy crises. Results show that by replacing existing natural gas water heaters with solar water heating system, it will be possible to reduce using fossil fuels and ultimately leads to a better environment. It is therefore, concluded that the option of solar water heating system may be adopted. References [1] [2] [3]
[4]
[5] [6] [7] [8] [9]
Pakistan Energy Yearbook, Hydrocarbon Development Institute of Pakistan, Islamabad, Pakistan, December 2010-11. K. Harijan, M.A Uqaili, M. Memon, k. Mirza, Forecasting the diffusion of wind power in Pakistan, Energy 36 (2011) 6068-6073. K. Mirza, N. Ahmad, K. Harijan, T. Majeed, Identifying and addressing barriers to renewable energy development in Pakistan, Renewable and Sustainable Energy Reviews 4 (2009) 927931. M.A. Uqaili, K. Harijan, M. Memon, K. Mirza, Potential of solar energy for cooking in rural areas of Pakistan, Proceedings, World Renewable Energy Congress-IX, Florence, Italy, August 19-25, 2006. Elsevier Science Ltd., U.K. A. Munawar, Renewable energy resource potential in Pakistan, Renewable and Sustainable Energy Reviews 13 (2009) 2696–2702. P. Prohit, A. Michaelowa, CDM potential of solar water heating systems in India, solar Energy 82 (2008) 799-811. A. Kalogirou, Solar thermal collectors and applications, Progress in Energy and Combustion Science 30 (2004) 231–295. REN21, Renewables 2011 Global status report. Information on http://www.census.gov.pk/MajorCities.htm
[10] RET Screen Software, Online user manual, Solar water heating project model chapter. www.retscreen.net [11] Economic survey of Pakistan, Economic Advisor’s Wing, Finance Division, Government of Pakistan, 2010-2011.
