Smart Frost Sensor

Frost – the tiny ice crystals that form when water temperature drops below 32 degrees F – is a major problem for heat pumps in HVAC and refrigeration units, on roads and transportation vehicles, and anywhere machines are exposed to cold temperatures. For example, in heat pumps and refrigeration, frost accumulation on evaporator surfaces substantially impedes the heat transfer process and degrades equipment performance. Current defrosting technologies lack precision, which usually leads to insufficient or excessive defrosting. This technology detects frost accumulation accurately, and can also identify initiation and termination of defrosting. It is a smart frost detector using nano- and micron-scale sensors for frost diagnostics and control, to enable initiating defrosting at the best time, and terminating defrosting when it senses melt water from frost is removed. No current technology offers this level of detection. 

Description

Typical defrosting technologies use a timer that runs a set amount of time, and automatically defrosts, whether it is needed or not. Frost causes a host of problems for evaporator units, HVAC equipment, and other machinery. This technology uses precise measurement to help identify when frost occurs and helps identify defrosting initiation and termination. Current technology cannot identify accurate frost accumulation and detect whether water is in a transfer phase, that is, if frost is melting or not, or if it’s dry. Defrosting controls are not capable of accurately identifying how much frost is melted and also ignore the evaporator coil surface condition during defrosting. This technology utilizes smart frost sensors for HVAC diagnostics and defrosting control. The sensor utilizes integrated measurement of capacitance, resistance, and temperature sensing to dynamically detect frost growth and identify the heat transfer surface during defrosting. This enables accurate frosting and defrosting control in real refrigeration and heat pump systems, resulting in a substantial improvement in energy efficiency. In addition to heat pump and refrigeration systems, this technology also could be used on roadways where black ice is present, on car and aircraft windshields, and other areas. 

Applications and Industries

• Residential and commercial refrigeration systems 
• Various heat pumps 
• Aircraft, vehicles and transportation infrastructure 

Benefits

• Smart sensor integrates capacitance, resistance and temperature sensing to detect frost 
• Increased energy efficiency 
• Accurate sensing of frost initiation and defrosting control