Experimental facility
With a view to develop an Atmospheric Water Generator (AWG) and a green air-conditioning system utilizing minimal electrical power (comparable to that of two to three fans) and no refrigerants, an ultra-low-grade heat-driven AWG and a dehumidifier prototype in the form of desiccant coated fin-tube heat exchangers have been fabricated and are being tested. Salient features of the prototype and the accompanying state-of-the-art facility are as follows:
(a) The prototype has a cross-section area of 0.15 x 0.3 m2 and can handle a flow-rate of 325 m3/hr. It can function well even in high humidity environments (with a specific humidity of 0.02 kg/kg dry air) and reduce/increase the specific humidity to 0.01/0.03 kg/kg dry air (0.01 kg/kg d.a. is typical of the room-supply-air condition of an air-conditioned space; air with specific humidity of 0.03 kg/kg d.a. can yield 3 grams of potable water per kg of dry air if it is brought in contact with a surface at 30 C, typical of ambient conditions).
(b) The nominal cooling capacity and the electrical COP are 3.5 kW (1 R-ton) and >10 respectively. The unit requires two water streams, one at the ambient temperature (~30 C) and other at a temperature below 50 C (low-grade heat). In cases wherein room-return air is available for regeneration, the warm water stream may also be at a temperature as low as <40 C (ultra-low-grade heat).
(c) The state-of-the-art test-facility (as shown in figure below) for testing the prototype comprises of two air flow-paths, 8 solenoid-actuator-controlled dampers, two blowers (for each of the conduits), equipment to mimic a wide-array of weather conditions as well as room conditions, as well as sensors (to measure temperature, RH, velocity, differential pressure). On the liquid-side, the setup also comprises of two water-flow-conduits comprising of pipes, solenoid-controlled 4-way valves as well as hot/cool water sources (water-bath and electric-water-heaters) and sensors (to measure Temperature, Differential Pressure, Flow-rate). Using a data-acquisition system, the steady and transient readings are captured and valves/dampers are periodically switched on/off.
