Patent ID: 7081688

Claim:
A method of operating an energy recovery apparatus in accordance with the following procedure, said apparatus comprising: a heat storage tank; a storage pump; a water lift pump for feeding water from said heat storage tank to an air-conditioning load; a first water feed pipe provided between an outlet port of said storage pump and said air-conditioning load; a second water feed pipe for returning water that is discharged from an outlet port of said air-conditioning load to said heat storage tank; a hydraulic turbine in fluid communication with said second water feed pipe, said hydraulic turbine comprising inlet valves and outlet valves; a hydraulic turbine bypassing valve for bypassing said hydraulic turbine; and a generator driven by said hydraulic turbine to produce electric power, said electric power being supplied to an electrical load, wherein at a time of starting operation of said apparatus: (1) said inlet valves of said hydraulic turbine open, said outlet valves of said hydraulic turbine close, and said hydraulic turbine-bypassing valve closes; (2) power is provided to a storage pump-driving electric motor; (3) a start signal is provided from said generator to said water lift pump; (4) operation of said water pump begins after passage of a predetermined time after receiving an operation answer signal; (5) said outlet valves of said hydraulic turbine open after passage of said predetermined time, thereby operating said hydraulic turbine and operating said generator to generate electric power; and (6) said electric power is supplied to said electric load, wherein at a time of stopping operation of said apparatus: (1) said outlet valves of said hydraulic turbine close, said hydraulic turbine is stopped, and said generator is stopped; (2) said generated electric power is no longer supplied so that said electric power is no longer supplied to said electric load; and (3) a stop signal from said generator is provided to said water lift pump, thereby stopping operation of said water lift pump.