Q vs Engineering Calculator HVAC

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HVAC engineering calculations in seconds — right on site, without an internet connection. Converting kgf/cm² to bar, checking the velocity in a pipe, sizing an expansion tank or picking a valve Kvs used to mean searching the web, leafing through a handbook and doing arithmetic in your head. Now your phone is enough. UNIT CONVERSION WITHOUT MISTAKES Enter a value once and see it in every unit of the category at the same time. Pressure, flow rate, power, energy, temperature, length, area, volume, mass and velocity: ten categories, about eighty units, including kgf/cm², mmH₂O, Gcal/h, BTU/h and psi. Any value is copied with a single tap, straight into an email or a bill of quantities. PIPE VELOCITY ACROSS EVERY SIZE AT ONCE Enter the flow rate and see the velocity for every pipe size, with a colour hint: where it is too low, where it is fine, where the pipe will get noisy. Steel to GOST 3262 up to DN 350, PP-R PN20, PEX and PE-RT, copper to EN 1057 — with real inner diameters, not nominal ones. Picking a diameter takes a couple of seconds. THERMAL POWER AND FLOW, BOTH WAYS Know the flow rate and you get the power. Know the power and you get the flow rate. Water, ethylene glycol and propylene glycol from 10 to 60 percent, with density and specific heat taken at the average temperature rather than approximated. The result comes in kW, kcal/h and Gcal/h at once. VALVES Pressure drop across a control or balancing valve from its Kvs, and the reverse task: which Kvs is needed for a given drop. In bar, kPa and metres of water column. EXPANSION TANK Required membrane tank volume, the nearest standard size, the expansion volume and the tank efficiency. The system volume can be estimated from the installed power. If the temperatures or pressures are inconsistent, the app says so instead of returning a neat but wrong number. PIPE INSULATION Surface area, area per metre, insulation volume and the insulated diameter — numbers ready for a bill of quantities. REFERENCE DATA INSIDE Steel water and gas pipes to GOST 3262 from DN 15 to DN 350, PP-R PN20, PEX and PE-RT, copper pipes to EN 1057. Water density and specific heat by temperature, properties of water and glycol mixtures, volumetric expansion coefficients, the standard range of expansion tanks from 5 to 1000 litres and typical insulation thicknesses by diameter. WHY IT WORKS ON SITE • Fully offline: no internet needed in a basement or on a construction site • Nothing extra: no ads, no sign-up, no subscriptions, no permissions • Input accepts both a comma and a dot, the numeric keyboard opens by itself • Russian and English, light and dark theme • Selected units and settings are remembered WHO IT IS FOR HVAC and plumbing designers, heating and water supply installers, service engineers of boiler houses and heat substations, energy auditors and students of related fields. Written by a practising HVAC engineer for himself and his colleagues. Free.