Gas and plumbing calculators. 68 tools for gas, heating and water maths.

Gas

q = \frac{V}{t}

GasHeat input from timed gas volume

P = \frac{V C c_{v}}{t}

GasGas volume demand from heat input

q = \frac{P}{c_{v}}

GasLPG / fuel mass consumption

\dot{m} = \frac{P}{c_{v}}

GasGas volume to billed energy

E = V C c_{v}

GasGas volume reference conversion

V_{ref} = V \frac{p}{p_{ref}} \frac{T_{ref} + 273.15}{T + 273.15} \frac{Z_{ref}}{Z}

GasGas pressure loss from supplied table data

Δ p = r (L + L_{eq})

GasPipe and installation volume

V_{total} = \frac{π d^{2} L}{4} + V_{other}

GasWobbe index

W = \frac{c_{v}}{\sqrt{SG}}

GasCO / CO₂ ratio

ratio = \frac{CO}{10^{4} \times {CO}_{2}}

Heating & hot water

Heating & hot waterHeat carried by flowing water

P = ρ c_{p} q Δ T

Heating & hot waterRequired heating-water flow

q = \frac{P}{ρ c_{p} Δ T}

Heating & hot waterFlow–return temperature difference

Δ T = \frac{P}{ρ c_{p} q}

Heating & hot waterEnergy to heat stored water

E = ρ V c_{p} (T_{h} - T_{c})

Heating & hot waterCylinder recovery time

t = \frac{ρ V c_{p} Δ T}{P}

Heating & hot waterPower for target recovery time

P = \frac{ρ V c_{p} Δ T}{t}

Heating & hot waterMixed-water temperature

T_{m} = \frac{q_{h} T_{h} + q_{c} T_{c}}{q_{h} + q_{c}}

Heating & hot waterHot and cold flow for a target mix

q_{h} = q \frac{T_{m} - T_{c}}{T_{h} - T_{c}}

Heating & hot waterUsable mixed-water volume

V_{m} = V_{h} \frac{T_{h} - T_{c}}{T_{m} - T_{c}}

Heating & hot waterInstantaneous hot-water temperature rise

Δ T = \frac{P}{ρ c_{p} q}

Heat loss & emitters

Heat loss & emittersFabric heat loss: one element

P = U A Δ T

Heat loss & emittersVentilation sensible heat loss

P = ρ c_{p} n V Δ T

Heat loss & emittersRadiator output at operating temperatures

Δ T = \frac{T_{f} + T_{r}}{2} - T_{a}

Heat loss & emittersRequired catalogue radiator output

P_{rated} = \frac{P}{{(\frac{Δ T}{{Δ T}_{rated}})}^{n}}

Heat loss & emittersBuffer energy-storage estimate

V = \frac{P t}{ρ c_{p} Δ T}

Heat loss & emittersUFH pipe-length estimate

L = \frac{1000 A}{s} + L_{tails}

Heat loss & emittersSolar thermal useful-power estimate

P = A G η

Water hydraulics

Water hydraulicsPipe velocity

v = \frac{4 q}{π d^{2}}

Water hydraulicsBore from target velocity

d = \sqrt{\frac{4 q}{π v}}

Water hydraulicsFlow from bore and velocity

q = \frac{π d^{2} v}{4}

Water hydraulicsReynolds number

Re = \frac{ρ v d}{μ}

Water hydraulicsStraight-pipe friction loss

Δ p = f \frac{L}{d} \frac{ρ v^{2}}{2}

Water hydraulicsFitting / local resistance loss

Δ p = K \frac{ρ v^{2}}{2}

Water hydraulicsStatic head to pressure

p = ρ g h

Water hydraulicsPressure to head

h = \frac{Δ p}{ρ g}

Water hydraulicsRequired liquid valve Kv

K_{v} = q_{m³/h} \sqrt{\frac{SG}{{Δ p}_{bar}}}

Water hydraulicsLiquid pressure drop from Kv

{Δ p}_{bar} = SG {(\frac{q_{m³/h}}{K_{v}})}^{2}

Water hydraulicsLiquid flow through a Kv valve

q_{m³/h} = K_{v} \sqrt{\frac{{Δ p}_{bar}}{SG}}

Water hydraulicsPump hydraulic and input power

P_{hyd} = ρ g q h

Water hydraulicsPump-speed affinity estimate

q_{2} = q_{1} r

Water hydraulicsDarcy friction factor

f = \frac{64}{Re} (laminar)

Expansion & materials

Expansion & materialsFluid expansion from density change

V_{e} = V_{cold} (\frac{ρ_{cold}}{ρ_{hot}} - 1)

Expansion & materialsExpansion-vessel acceptance estimate

a = p_{0,abs} (\frac{1}{p_{fill,abs}} - \frac{1}{p_{max,abs}})

Expansion & materialsPipe thermal expansion

Δ L = α L Δ T

Expansion & materialsPressure force on an end cap

F = \frac{p π d^{2}}{4}

Geometry & drainage

Geometry & drainageRound pipe water content

V = \frac{π d^{2} L}{4}

Geometry & drainageCylindrical tank volume

V = \frac{π d^{2} h}{4}

Geometry & drainageRectangular tank volume

V = L w h

Geometry & drainageMeasured bucket flow

q = \frac{V}{t}

Geometry & drainageFill / drain time at constant flow

t = \frac{V}{q}

Geometry & drainageDrainage fall for a chosen gradient

h = \frac{L}{N}

Geometry & drainageGradient from rise / fall and run

N = \frac{L}{h}

Geometry & drainageTwo-bend pipe offset

T = \frac{O}{\sin θ}

Geometry & drainageRolling offset using two 45° bends

O = \sqrt{R^{2} + S^{2}}

Energy & electrical

Energy & electricalThermal efficiency

η = \frac{P_{out}}{P_{in}}

Energy & electricalFuel input from useful output

P_{in} = \frac{P}{η}

Energy & electricalHeat-pump COP

COP = \frac{P_{heat}}{P_{elec}}

Energy & electricalRunning energy and cost

E = P t

Energy & electricalResistive heater current

I = \frac{P}{U}

Energy & electricalHeating-element resistance

R = \frac{U^{2}}{P}

Unit conversions

Unit conversionsLength converter

result = value

Unit conversionsVolume converter

result = value

Unit conversionsPressure converter

result = value

Unit conversionsPower converter

result = value

Unit conversionsEnergy converter

result = value

Unit conversionsVolume flow converter

result = value

Unit conversionsTemperature converter

result = value

Unit conversionsMass converter

result = value

Gas and plumbing calculators. 68 tools for gas, heating and water maths.

Gas

Heating & hot water

Heat loss & emitters

Water hydraulics

Expansion & materials

Geometry & drainage

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