VCare contribution to the environmental sustainability
Compound parabolic concentrators used for industrial process heating in kandla
VCare global is a vadodara-based engineering company which aims to utilize solar energy for industrial, commercial, and residential applications to provide sustainable and enviro-friendly solutions.
VCare global is committed to promote renewable technologies in industries. Traditionally, the industrial sectors are largely dependent on conventional fuels to meet their heating applications. Since its establishment in 2005, vcare global has been researching, developing, and implementing affordable novel solutions of renewable and clean energy for providing process heat and air-conditioning for the industrial, commercial, residential, and hospitality sector. One of such proven, highly efficient, and economical solar thermal technology is compound parabolic concentrator (cpc). Cpc is suitable for generating hot water up to 90 100c. Vcare global has applied and commissioned cpc technology for hot water generation at kandla free trade plant for a leading fmcg companyhindustan unilever ltd.
Need for cpc system
Earlier the process heating requirement at hindustan unilevers kandla plant (picture 1) was met by diesel. The key concernsthe costing of diesel, its contribution to environmental pollution, including global warmingwere the key drivers that led the company to consider alternative cleanersolutions. Hindustan unilever decided to switch over to solar technology for heating 20 kl of process water during one shift operation. The water is heated from 30c to 85c, accounting for 11 lakh kcal.
To meet the heating requirements, vcare global proposed a comprehensive solution, based on compound parabolic concentrator technology. The solution comprised of 160 collectors providing a total aperture area of 480 m2.
The system has a primary circuit consisting of cold water storage, cold water pumping to the cpc in series and parallel laid on 3 arrays and collecting the generated hot water in the hot water tank (figure 1). The cpc was designed to give 11 lakh kcal per shift operation on an average basis. To achieve the desired temperature of 85c on the secondary side, it was designed to raise the temperature of hot water up to 92c in the primary circuit, using solar energy generated from cpc.
While india has abundant coal, it is of poor quality causing substantial harm to the environment. India has meagre clean fossil fuels like oil and natural gas. The country has no option except to adopt renewable forms of energy, such as solar, hydro, wind and biogas/biomass. On a micro level, industries across the country face the problem of rising fuel costs compounded by regulatory edicts from the state environmental boards that are becoming stricter by the day. Cost reduction was certainly an objective for hindustan unilever and at the same time, being a steward of a clean environment.
Unilever requested VCare Global to offer sustainable solutions to reduce its carbon footprint. The various technologies for solar process heating included Flat Plate Collectors, Evacuated Tube Collectors, Parabolic dishes, Parabolic Trough Concentrators, and Fresnel Linear Concentrator. VCare zoomed in on CPC as it was the most suited technology for such an application.
The biggest challenge faced by VCare was the selection of the appropriate technology from the available ones. VCare, being an engineering company, sees itself as solution provider. It reviewed the various options and systematically analysed pros and cons of options such as Flat Plate Collectors and Evacuated Tube Collectors (ETC) to offer options those which are high on efficiency, cost effective but had limitation of temperature that could be attained (are good up to 80°C) and on other hand there were technologies like parabolic dish concentrators, parabolic trough concentrators, LFR, etc. After careful evaluation looking at land available, usage pattern, user preference and capabilities, ease of operation and maintenance and no need for tracking CPC was decided upon. The integration of the existing system with solar was also a major challenge as the process was critical and any failure of the system to deliver could have meant production losses. Space is a challenge for any solar thermal heating system. In this context, the Kandla project was no exception. VCare Global mitigated the challenge by designing the layout of CPC panels in a most space-minimizing way.
Another Challenge was installation of system on the site as soil conditions had to be analysed to determine type of civil foundation. The limited working time allowed at the plant (only during daytime), was another challenge, and of course being monsoon, many days of site work was delayed as civil and insulation work could not be undertaken during the period; despite this the time line had to be maintained.
The Unilever team is satisfied with the system performance and the user-friendly control system provided with the PLC panel, and SCADA. With this, they can measure, control, monitor, and analyse the system performance.
The client has started taking benefits by using the Solar Thermal Hot Water System of saving in daily diesel consumption at about 127 ltr/day and also reduction in CO2 emission of about 126Ton CO2 per annum of 300 days operation.