Absorption-Based Heater for More Efficient Residential Water Heating

Architecture Uses Thin-Film Absorption and Desorption for Compact Size and Lower Manufacturing Costs

This absorption-based heater design uses a flow loop to capture low grade heat for heating and cooling purposes at higher efficiency for residential water heating. Ultra-thin absorbers and desorbers and the manner in which the process fluid is pumped achieve high heat exchange efficiency in this compact machine. Due to their large size, absorption-based heaters have been the domain of primarily industrial applications; available technology is not scalable or feasible for residential water heating. However, this architecture significantly reduces product size to allow for convenient residential and commercial usage while increasing the coefficient of performance. Researchers at the University of Florida have developed a compact, high-efficiency, open absorption cycle device capable of dehumidification, water heating, and evaporative cooling. Instead of transferring heat between two solution streams (i.e. heat recovery), the heat from the hot solution is transferred to the process fluid that is to be heated.

Application

Flow architecture for water heater simplifies the design and enhances the heating capacity of the system

Advantages

• Uses membrane-based thin-film absorption technology, allowing for compact design suitable for residential use
• Smaller and compact in size, lowering production costs
• Process flow loop architecture simplifies the design and enhances the heating capacity

Technology

Absorption heating technology utilizes phase change heat of the refrigerant (water vapor) for heating purposes, traditionally used with shell and tube heat exchangers for large-scale applications only. A process water flow architecture allows for a more compact absorption-based water heater. At its core, the heater features an open absorption cycle in which the water heater releases its latent heat into the absorber. The released heat is subsequently transferred into the process fluid that cools the absorbent. The solution is regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed, and its heat of phase change is transferred to the process fluid. Researchers at the University of Florida developed the absorption and desorption surface structures that enable this water heater. This design allows for a substantial reduction in size and cost while yielding higher capacity; the flow architecture can benefit any absorption-based heat pump.