Two kinds of heat in every airstream Any heated or cooled air carries energy in two forms. Sensible heat changes the dry-bulb temperature of the air without changing its moisture content. Latent heat is the energy tied up in water vapour: it moves when moisture condenses or evaporates, and it can change without any temperature […]
Psychrometric Processes in Heat Recovery: What Happens on the Chart
Four basic processes On the psychrometric chart, ventilation air moves along predictable lines: Heating: horizontal line to the right (dry-bulb up, moisture constant). Sensible cooling: horizontal line to the left (dry-bulb down, moisture constant). Humidification: line upward (more moisture). Dehumidification: line downward (condensation, latent heat released). Sensible recovery = a move along the constant-humidity line […]
Heat-Pump Low-Temp Drying: Air-to-Air Recovery
Why Low-Temperature Heat-Pump Drying Conventional grain, fruit and herb drying often uses direct fossil-fired hot air above 80-120 C. That high temperature damages colour, aroma and nutrients and wastes energy. Heat-pump drying supplies warm air at 30-60 C, which protects product quality while still removing moisture. The catch is that the exhaust leaving the drying […]
Rotary Heat Exchangers in Grain Drying Towers
Grain Drying and Its Energy Load Grain drying towers (grain driers) blow heated air through a bed of corn, rice or wheat to carry away moisture. The exhaust leaving the tower is hot and humid, so a large share of the burner’s fuel simply leaves as waste heat in that damp airstream. Cutting that loss […]
Waste Heat Recovery Across China Process Industries
The Resource at Stake China generates the largest industrial waste-heat resource on the planet – equivalent to more than 1 billion tonnes of standard coal per year, of which over 300 million tonnes are economically recoverable. Yet comprehensive utilisation runs at only about 32%, against roughly 56% in the EU, signalling a large efficiency gap. […]
China Dual-Carbon (3060) Policy as a Driver for Heat Recovery
The 3060 Commitments China has pledged to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060 (the ‘Dual Carbon’ or 3060 goals). Meeting them hinges on industrial energy efficiency – and waste-heat / recovery equipment sits squarely in the toolbox. Key Policy Documents 2024-2025 Energy Conservation and Carbon Reduction Action Plan (State […]
Heat Recovery Ventilation in Schools and Classrooms
Why Schools Need Heat Recovery Ventilation Classrooms are among the most densely occupied spaces in any building. With 20 to 30 students per room and high metabolic CO2 loads, ventilation rates under ASHRAE 62.1 approach 10 to 15 litres per second per person. Without recovery, exhausting that air year-round means discarding both heating energy in […]
Variable Refrigerant Flow (VRF) Heat Recovery Systems
What Is VRF Heat Recovery Variable Refrigerant Flow (VRF) heat recovery systems use a single refrigerant loop with branch selector boxes to deliver simultaneous heating and cooling to different zones. Recovered heat from cooling zones is redirected to zones calling for heat, reducing the building net energy use. Heat Recovery vs Heat Pump VRF Two-pipe […]
Heat Recovery in Greenhouses and Horticulture
The Energy Challenge Greenhouses and indoor farms maintain warm, humid conditions around the clock. Heating can be 30 to 50 percent of operating cost, while transpiration loads create enormous latent heat in the exhaust air. Recovering Heat from Exhaust and Condensation Air-to-air plate exchangers recover sensible heat from ventilation exhaust; condensing heat-recovery units capture latent […]
Thermal Comfort and Heat Recovery: ASHRAE 55 and IEQ
ASHRAE 55 and Thermal Comfort ASHRAE 55 defines acceptable thermal environments through the PMV or PPD model, balancing air temperature, mean radiant temperature, humidity, air speed and clothing. Heat recovery changes supply-air conditions, so it must be designed without degrading comfort. Humidity and IEQ Enthalpy recovery transfers moisture as well as heat, helping hold indoor […]