Prospects of solar water heating in textile industry
Issue Time:2016-07-28

Pakistan is an energy-deficient country and is a net importer of energy since the local fossil fuel reserves can meet only a small fraction of its needs.

Pakistan however has been blessed with the more beneficial and sustainable alternative in the form of renewable energy resources.

Renewable energy is the form of energy that is derived from natural resources such as sun, wind, water, biomass and waves. These forms of energy get the name renewable since they renew themselves instantly or within a very short period of time and there is no threat of depletion of their reserves. Renewable energy is gaining huge interest world wide, especially amongst the developed countries.

Pakistan has vast potential for renewable energy development; all of the four provinces i.e. NWFP, Balochistan, Sindh and Punjab have abundant sunshine since Pakistan is ideally located in the sunny belt to take advantage of solar energy technologies.

Pakistan in general gets a full sunshine for more than 300 days in a year. Sindh and Balochistan have excellent locations for capturing wind energy. Hydropower being another great asset for Pakistan implies that the country is extremely rich in terms of all the three major renewable energy resources of the present age i.e. solar energy, wind power and hydropower.

The geographical location, topography and local climate of the country favour the exploitation of these resources. Solar and wind energy systems are the leaders in the race. Generally these technologies, presently, are economically more expensive than other conventional energy systems such as fossil fuels and nuclear power.

Especially for a developing country like Pakistan these are not economically viable at all. However there is an exception in the family of renewable technologies - solar water heating - that is technically mature and economically viable even for a developing country like Pakistan.

There is an enormous potential for solar water heating in Pakistan's industrial and domestic sector. Hot water is not only an essential requirement in domestic housing but also in a number of industrial areas such as textile, beverages, food and other processing units. Solar water heating like other renewable energy technologies has only the initial capital cost and does not have any running cost.

Although its capital cost is considerable but the zero running cost makes it a much cheaper choice in the long run. For the industries the benefits of adopting solar water heating technology are manifold.

Firstly, it will help sharing the energy requirements with the industry and thus will provide a relief in terms of lesser reliance on already deficient energy resources. Secondly, it will be economically cheaper and thirdly it will cut down the environmental loads associated with water heating.

Textile industry is the backbone of Pakistani economy. Besides having a gigantic contribution of 60 per cent in the total exports of the country, it also has a share of 38 per cent in country's employment sector.

Pakistan is amongst the most prominent cotton producing countries in the world. The affluent availability of local cotton has led to a well established textile sector in Pakistan. A large proportion of its cotton products go into export.

Being a successful candidate in international market, Pakistani textile industry is continuously seeking modern and high-tech facilities to improve quality of its products.

One of the biggest challenges Pakistani textile industry is facing today is how to cut down its environmental burdens to cope with the international standards on the issue.

To sustain its leading role in export markets, Pakistan has to comply with international environmental protocols. The Pakistan Agricultural Research Council has warned that Pakistan's textile exports face a bleak prospect in the coming years unless the government adopts focussed measures to address the concerns relating to environment and updating of technology. In fossil fuel-run textile units, toxic emissions into the air and ground water are the major environmental concerns.

In the post-January 2005 quota-free market scenario, it will be inevitable to implement quality standards such as ISO 9001 and environmental standard ISO 14000. It is therefore very important for the textile industry to adopt environmentally efficient technologies to address any future challenges. At present there are hardly any textile industries in Pakistan that have addressed the issue.

Like most of other industrial sectors, textile industry requires a continuous supply of water. The major application of water in textile industry is in dyeing process.

Water is required not only at normal temperature but also at temperature as high as 80C. Heating up water at such a high temperature consumes considerable energy. Water if heated through conventional energy sources consequently has environmental impacts in the form of greenhouse gases and other toxic elements released both in air and water.

At present almost every major textile group is fitted with its own power plant. These internal power plants are normally run by furnace oil or gas. In either case this is environmentally an expensive choice. Solar energy is an ideal candidate to replace the presently employed water heating technologies in textile sector.

Solar water heating is an environmentally clean choice since it does not generate any kind of toxic or polluting element and hence can significantly reduce the environmental loads of a textile unit. Here it must be realized that solar water heating is dependant on availability of sunshine and hence cannot work during nocturnal hours.

Also, during the winter season when sunshine hours are lesser or during monsoon season with cloudy conditions the performance of the solar heater will be affected. It must also be noted that solar water heating system can easily comply with the domestic hot water needs since it can raise the water temperature upto 60-70 C which is hot enough for domestic applications (normally for bath in winter, warm water is required at a temperature of 40 C).

However in industrial applications hot water is required at almost 80-90 C, which can not be solely achieved by a solar heater. To overcome any seasonal poor performances or very high temperature water requirements solar water heaters can be coupled with conventional systems.

Earlier this year, a pilot project of solar water heating system was designed and installed by the author and his colleagues in a prominent textile mill in Pakistan.

The particular textile mill has a daily requirement of 120,000 liters of water at 80-85C. It was decided to initially install a pilot project to evaluate the performance under the particular seasonal and environmental conditions.

The installed solar heater has a capacity of heating 160 liters of water per day upto 60-65 C (although the water temperature has been observed hitting 80C in May/June months).

The installed solar heater was completely manufactured from the materials locally available in Pakistan and has been running for four months now. The results of the heater are extremely promising as it raises the water temperature from normal (25-30C) to 60-65C.

The remaining temperature difference can be met with the conventionally operated boilers. Results show that a net energy saving of 60-70 per cent is achievable through incorporating solar water heaters within the existing textile industry set-ups. It also indicates that the environmental impacts associated with water heating can also be reduced to 30-40 per cent.

It is now planned to increase the capacity of water heaters upto 10,000 liters/day by the end of this year. Later the system will be further magnified to meet the total requirement of the mill, which is 120,000 liters/day.

Solar water heaters like other renewable technologies only involve capital cost. Since they do not have any running cost their payback period is quite small. The payback period of the installed solar water heater almost five years while it has a service life of well over 30 years.

Solar water heaters, which are easy to build and install, can pay back the total cost within 5 years and afterwards can provide free hot water for decades. For Pakistani textile industry particular this technology has many fold advantages and hence it is needed that textile sector should come forward and take on with this technology that is totally indigenous and is easy to adopt.

It should also be noted that within domestic sector solar water heaters can give a big relief by bringing down gas/electricity bills. Here it must also be kept in mind that energy deficiency is one of the basic hurdles in Pakistan's economic development and solar water heating or any other such exercises will be of benefit to the country.