New solar pump draws 40 p c more water, consumes less power

Hyderabad, Apr 12 (UNI) The Corporate R&D of Bharat Heavy Electricals Limited (BHEL) is ready with a new version of solar powered deepwell pump which can draw about 40 per cent more water with hardly much increase in electricity consumption.

A high-efficiency low-cost deep well solar photovoltaic (SPV) water pumping system capable of bailing water from depths ranging from 30 mtrs (100 ft) to 230 mtrs (750 ft) had been developed by Corporate R&D last year. The system is useful for applications in large buildings, hospitals, multi-storied apartments, hotels, residential colonies, industrial units, remotely located drinking water supply schemes and agricultural-horticultural farmlands. As a major technological enhancement, two Automatic Active Solar Trackers (AAST) have been added to the system.

The trackers are developed on the basis of the concept that the solar radiation energy level on the horizental surface of earth keeps changing from low in the morning to peak value at noon and again becomes low in the evening, as the sun moves from east to west.

The maximum available solar energy can be received on the photovoltaic module or array if it is kept facing the sun all the time from morning to evening by using a sun tracking mechanism.

The newly developed AAST is environment-friendly and uses a very small portion--less than 5 watt-hour per day--of the photovoltaic energy available from the same photovoltaic array which is being tracked. Due to this addition the daily water output has gone up from 19,300 litres per day (LPD) at 40 m head to 26750 LPD.

The whole frame, supported by four hinges, is automatically tracked using a motor driven screw-jack, which pulls or pushes the frame from east to west and vice versa. The power from photovoltaic array is used to automatically drive the motor in steps using a small controller. Very little power is required to drive the motor.

The structure is designed to withdstand wind speed of 150 km/hour, Corporate R&D Group General Manager S K Goyal told media here today.

With experience gained in the development of the 100 LPD solar geysers and in tune with the market demand, 250 LPD solar water heating system with heat pipes and two prototypes were developed and installed for long term testing.

The system delivers 250 litres of hot water per day at a temperature of 60 degrees C to 70 degrees C. The 250 LPD system based on heat pipe collector is much more efficient, compared to a standard thermo-syphon system, as there is no heat loss due to reverse circulation during the night, since the heat pipe acts as a thermal diode. The system will meet the requirement of largescale users, since it can be connected in series and parallel combinations to meet the required quantity of hot water, he added.

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