Energy recovery wheel Transfers both sensible and (if enthalpic) latent heat between supply and exhaust air. Goal: cut HVAC heating/cooling load. Made of aluminum or polymer matrix, sometimes with a moisture-absorbing coating. Desiccant wheel Impregnated or coated with a desiccant (silica gel, molecular sieve, or zeolite). Its job is dehumidification – it pulls moisture from […]
Geothermal and Ground-Source Air Pre-Heating
The earth a few meters below the surface stays near constant temperature all year. That stable thermal mass can be used to pre-condition ventilation air before it reaches a building, cutting heating and cooling loads. How Ground Coupling Works Outdoor air is passed through a buried pipe loop (ground heat exchanger) or across a ground-coupled […]
Air-to-Air vs Air-to-Water Heat Recovery
Heat recovery comes in two broad forms. Air-to-air exchangers move heat directly between two air streams. Air-to-water devices (like run-around coils or exhaust water heaters) transfer heat into a fluid loop that can serve distant or mixed loads. Side-by-Side Factor Air-to-Air Air-to-Water Streams Two air ducts Air + water/glycol loop Distance Short (cores co-located) Long […]
Air Handling Units (AHU) and Heat Recovery Integration
An air handling unit (AHU) conditions outdoor air before it enters a building. Without recovery, that outdoor air must be heated or cooled from scratch every hour. Adding a heat recovery core to the AHU is the single highest-impact energy measure for ventilation systems. Where the Exchanger Sits in an AHU The recovery core is […]
Marine and Corrosive Environment Heat Exchangers
Ships, offshore platforms, and chemical plants expose heat exchangers to salt spray, high humidity, and aggressive gases. In these corrosive environments, material selection is as important as thermal design. Material Options Hydrophilic aluminum: Good for clean marine ventilation, low cost. Stainless steel (304/316L): Resists salt and many chemicals; heavier and pricier. Epoxy / phenolic coated […]
Enthalpy Recovery vs Sensible Recovery
Heat recovery is often described as “sensible” or “enthalpy.” The difference decides comfort, energy savings, and which technology to specify. Sensible Recovery Transfers temperature only. Plate exchangers, heat pipes, and run-around coils are sensible devices. They pre-heat or pre-cool the supply air without adding or removing moisture. Enthalpy Recovery Transfers both temperature and moisture. Enthalpy […]
Run-around Coil Heat Recovery Systems
A run-around coil heat recovery system uses two finned coils connected by a closed glycol loop. A pump circulates the fluid between the exhaust coil, where it picks up heat, and the supply coil, where it releases heat into the incoming air. When to Use a Run-around Coil This design is ideal when the supply […]
Plate Heat Exchanger: Working Principle, Types and Applications
A plate heat exchanger is one of the most efficient ways to recover thermal energy from exhaust air, process gas, or ventilation streams. It consists of multiple thin metal plates separated by gaskets or formed air gaps, creating alternating channels for the hot and cold streams. Heat moves through the plate material without the two […]
Rotary Heat Recovery Wheel: Sensible and Enthalpy Types
A rotary heat recovery wheel is a rotating honeycomb disc that slowly turns between the supply and exhaust air streams. As it rotates, the wheel absorbs heat from the exhaust air and releases it into the incoming fresh air. In enthalpy wheels, moisture is also transferred, making them ideal for humidity control. How It Works […]
Heat Pipe Heat Exchanger: Passive Thermal Transfer
A heat pipe heat exchanger uses sealed tubes filled with a working fluid to move heat from one air stream to another. It has no moving parts, requires no external power, and keeps the two streams physically separated. Working Principle Each heat pipe is a sealed tube with an internal wick structure. At the hot […]