Research Project Summary Information
Solar Thermal Metal Hydride Heat Pumps for ERV's (ST10928-1)
Ergenics Solar Thermal Heating and Cooli
The advantages of applying a Heat Recovery Ventilator (HRV)/Energy Recovery Ventilator (ERV) system to a well designed home are understood. In the New York environment, supplemental heat is required in the winter and dehumidification is desirable for summer. A single system that provides both functions using solar thermal energy will achieve the ultimate in comfort, efficiency and reduced system cost. The hydride heat pump functioning within an HRV/ERV is an extension of a solar thermal driven hydride air conditioning technology currently being developed. Adding supplemental cooling and heating to an existing ERV system that provides whole house ventilation, could become the source of both cooling and heating for the entire home.
Existing Energy Recovery Ventilation (ERV) units will be examined for their ability to be integrated with a reversible metal hydride heating/cooling system. The metal hydride is an alloy that freely expands and contracts, while effectively transferring heat via thermal kinetics. Harnessing this process provides cooling and recharging, similar to what happens in a conventional refrigerant based compressor/ condenser air conditioning unit. The Contractor will perform a detailed evaluation of the technical and economic parameters of this cycle, to determine feasibility. If feasible, a bench-top prototype will be developed to test on an ERV system.
The benefits of integrating an ERV/HRV with a reversible metal hydride heating/cooling system include:
(a) lower energy use, conventional A/C compressor that draws 740 watts replaced by solar thermal powered metal hydride heat pump that draws 150 watts. Annual electric operation cost savings would be $85, with additional incremental capital cost of $1,000 to outfit an ERV/HRV with the hydride system ($1,000+$1,250), when including installation/ductwork (another $1,250) this yields a total first cost of $3,500. Compared to $9,000 first cost for centralized A/C only including installation ductwork, would yield a $5,500 first cost difference along with an $85/yr. operation cost savings. * example excludes any heating system provided in the first cost, Centralized A/C typically appended to a FHA furnace ($4,000)for heating, while ERV/HRV optimum choice for heating plant would be a hydronic system ($4,000 - $5,000). Market transformation may involve an interim stage of FHA and ERV combination.
(b)less maintenance, metal hydride heat pump is hermetically sealed unit without rotating or sliding seals and requires no refrigerant
(c) dehumidification coupled with cooling, provides dehumidification with 48 deg. F chilled water
(d)provides all in one mechanical solution for well built homes of NY State.
The project results include:
•An improved design that addresses piping configuration and replacement of 3-way valves with 2-way valves, that will improve performance (dehumidification capability and chilled return water) of the metal hydride heat pump.
•Demonstration of a prototype with a measured coefficient of performance (COP) of 0.26. With mechanical improvements a COP of 0.7 is expected(1 BTU heat input => produce 0.7 BTU cooling).
•The prototype provided over 7,000 BTU/h (> 2 kW) of cooling, exceeded design base maximum of 6,400 BTU/h.
•With an average ambient temperature of 77 deg F. during test, the prototype produced average water temperature of 56.3 deg F. (design modifications will lower this water temp. near 48 deg. F for optimum dehumidification)
•The combined electrical power consumption for water pumps, heat rejection fans and controls was 690 watts, with minimal design improvements this will be decreased by 200 watts (490 watts) then with aggressive optimum design, total power consumption to 150 watts.
Ergenics Solar Thermal Heating and Cooli
373 Margaret King Avenue
Ringwood, NJ 07456
NYSERDA Contact Information
R&D -Transport & Power Systems