Definition The outdoor-air ratio (OAR) is the share of supply air that is genuinely fresh outdoor air: OAR = outdoor_air_flow / total_supply_air_flow A space with no recirculation runs at OAR = 1 (100% outside air). Where OAR is forced to 1 Some spaces cannot recirculate for safety or code reasons: Cleanrooms and graded pharmaceutical suites […]
Face Velocity: The Single Number That Sets Core Size and Pressure Drop
Definition Face velocity is the approach speed of air entering the core face: face_velocity = volumetric_flow / core_face_area It is measured in metres per second (m/s). Typical range For HVAC air-to-air cores, face velocity usually sits between 1.5 and 3.5 m/s. Lower is gentler on the core and the fan; higher packs more flow into […]
Plate vs Rotary Exchangers for Drying: Selection
Why the Exchanger Type Decides Drying Quality Drying and baking exhaust typically leaves the process at 50–90°C and 15–40 g/kg absolute humidity. Recovering that energy cuts fuel or electricity by 15–40%, but the wrong recovery device can re-wet the product, contaminate the supply air, or freeze in winter. Plate and rotary-wheel exchangers solve the same problem […]
Liquid vs Air Cooling for Battery Storage
The Thermal-Management Shift in Grid Storage Utility-scale battery energy storage has moved from 0.5C cabinets to 1C–2C container systems of 3–5 MWh and beyond. At those power densities, keeping every cell in a tight temperature window is no longer optional — it decides cycle life, safety, and usable capacity. That is why the industry is migrating […]
Why BESS & PV Inverters Use Counter-Flow Cores
The Cooling Problem in Energy Storage and PV Inverters Battery energy storage system (BESS) cabinets and photovoltaic (PV) inverters concentrate high-power electronics – IGBT modules, DC/DC converters, reactors and capacitors – into sealed outdoor enclosures. These components dissipate heat at high flux density; if the internal air is not kept cool, semiconductor junction temperatures rise, […]
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 […]
Sourcing Recovery Equipment from China
Why Buyers Look to China China’s heat-exchanger clusters offer a mature supplier ecosystem, short lead times and strong price-performance. For air-to-air recovery cores – plate, enthalpy wheel, heat pipe and run-around coil – Chinese makers supply both branded lines and private-label OEM/ODM volumes to global HVAC brands. Certifications to Expect CE marking for the European […]