Katsambas Engineering Tools

Cooling Load

ASHRAE CLTD method — residential & commercial

Floor Area (m²)

Occupants

Sun Exposure (0.5–2.0)?

Ceiling Height (m)

Climate Zone (1–6)?

Window Area (m²)

Orientation

Wall Insulation?

Cooling Load Results

—kW—

Tons of Refrig.

—

BTU/hr

—

BTU/hr

Load Breakdown (detail)

Envelope

—

Occupants

—

Solar

—

Lighting

—

Equipment

—

Ventilation

—

Heating Load

Fabric + ventilation heat loss per ASHRAE / EN 12831

Floor Area (m²)

Ceiling Height (m)

U-Value Wall (W/m²K)

U-Value Roof (W/m²K)

U-Value Floor (W/m²K)

U-Value Window (W/m²K)

Window Area (m²)

Internal Temp (°C)

External Design Temp (°C)

Air Changes / Hour?

Occupants

Heating Load Results

—kW—

W per m²

—

W/m²

Delta T

—

°C

Heat Loss Breakdown (detail)

Walls

—

Roof

—

Floor

—

Windows

—

Ventilation

—

Duct Sizer

Equal friction method — ASHRAE HVAC Applications Handbook

Airflow (m³/s)

Duct Type

Material

Aspect Ratio (W:H)?

Duct Sizing Results

Circular Diameter

—

Rect. Width × Height

—

mm × mm

Design Velocity

—

m/s

Friction Loss

—

Pa/m

Dynamic Pressure

—

Cross-Section Area

—

m²

DuctSizer Pro

Full McQuay DesignTools-style solver — tick any 2 known values, solve for everything else

Fluid

Material / Roughness

Fluid Density

1.2014 kg/m³

Fluid Viscosity

0.0643 kg/m·h

Specific Heat

1.0048 kJ/kg°C

Energy Factor

1.21 W/°C·L/s

Tick the 2 values you know, enter them, then click Solve

✦ Flow rate L/s

✦ Head loss Pa/m

✦ Velocity m/s

✦ Equivalent diameter mm

✦ Duct size W × H mm × mm

Select 2 known values above

DuctSizer Pro — Results

Equivalent Diameter

—

Recommended Round Duct

—

mm standard size

Flow Area

—

cm²

Fluid Velocity

—

m/s

Flow Rate

—

L/s

Flow Rate

—

m³/h

Reynolds Number

—

Friction Factor

—

Darcy-Weisbach

Velocity Pressure

—

Head Loss

—

Pa/m

Duct Size (if rect)

—

mm × mm

Flow Regime

—

Ventilation Sizing

ASHRAE 62.1-2022 Ventilation Rate Procedure

Floor Area (m²)

Occupants

Space Type

System Type

Ventilation Results — ASHRAE 62.1

OA Flow Rate

—

L/s

OA Flow Rate

—

CFM

Air Changes / hr

—

ACH

Supply Air

—

m³/s

Per Person

—

L/s·person

Per m²

—

L/s·m²

Fan Power

Shaft and motor power from airflow and total pressure

Airflow (m³/s)

Total Pressure (Pa)

Fan Efficiency (%)

Motor Efficiency (%)

Altitude (m)

Fan Results

Motor Power

—

Motor Power

—

Shaft Power

—

Overall Efficiency

—

Air Density

—

kg/m³

Airflow

—

CFM

Pipe Diameter

Velocity method with Darcy-Weisbach friction loss

Flow Rate (m³/s)

System Type

Fluid

Pipe Material

Pipe Sizing Results

Calculated Diameter

—

Recommended DN

—

Velocity

—

m/s

Pressure Drop

—

Pa/m

Reynolds Number

—

Fluid

—

Pressure Drop

Darcy-Weisbach with Colebrook-White friction factor

Flow Rate (m³/s)

Pipe Diameter (mm)

Pipe Length (m)

Fittings Equiv. Length (m)?

Fluid

Pipe Material

Pressure Drop Results

Pressure Drop

—

Pressure Drop

—

kPa

Velocity

—

m/s

Reynolds Number

—

Friction Factor

—

Darcy

Pressure Drop

—

bar

Pump Power

Hydraulic and motor power sizing

Flow Rate (m³/s)

Total Head (m)

Fluid

Pump Efficiency (%)

Motor Efficiency (%)

Pump Results

Motor Power

—

Motor Power

—

Hydraulic Power

—

Shaft Power

—

Overall Efficiency

—

Flow Rate

—

L/s

Refrigerant Pipe Sizing

ACR copper pipe selection per ASHRAE Refrigeration Handbook

Capacity (kW)

Refrigerant

Line Type?

Line Length (m)

Refrigerant Pipe Results

Calculated OD

—

Recommended ACR Size

—

Design Velocity

—

m/s

Mass Flow

—

kg/s

U-Value Calculator

Composite thermal transmittance per ISO 6946 — up to 5 layers

Layer 1 Thickness (mm)

Layer 1 λ (W/mK)

Layer 2 Thickness (mm)

Layer 2 λ (W/mK)

Layer 3 Thickness (mm)

Layer 3 λ (W/mK)

Layer 4 Thickness (mm)

Layer 4 λ (W/mK)

Layer 5 Thickness (mm)

Layer 5 λ (W/mK)

U-Value Results

—W/m²K

R-Value

—

m²K/W

R-Value (Imperial)

—

ft²·hr·°F/BTU

Heat Exchanger Sizing

LMTD method — counterflow or parallel flow

Hot Inlet Temp (°C)

Hot Outlet Temp (°C)

Cold Inlet Temp (°C)

Cold Outlet Temp (°C)

Flow Rate (m³/s)

U-Value (W/m²K)

Flow Arrangement?

Heat Exchanger Results

Heat Duty

—

Required Area

—

m²

LMTD

—

°C

Effectiveness

—

NTU

—

Heat Duty

—

BTU/hr

VENTUS C2020 Slot Grilles

Grille & spigot selection — University of Patras experimental data (Dr. Dionysis Margaris)

Total Airflow (m³/h)

Grille Length (m)

Spigot & Deflector Config?

C2020 Grille Results

Grille	Free Area (m²)	Velocity (m/s)	Throw (m)	ΔP (Pa)	Noise (dB)

Spigot Selection

VENTUS Linear, Slot & Camouflage

Linear C8-5 / C12-5, V-Cut C10-7, 2-Slot, 3-Slot, Camouflage — University of Patras data

Total Airflow (m³/h)

Grille Length (m)

Grille Type

Grille Performance Results

Free Area

—

m²

Velocity

—

m/s

Throw (to 0.5 m/s)

—

Pressure Drop

—

Noise

—

Flow / metre

—

m³/h·m

Spigot Selection

Project Rooms

One room record feeds Cooling, Heating & Ventilation — save results back here instead of retyping

Room Name

Floor Area (m²)

Occupants

Ceiling Height (m)

Window Area (m²)

Orientation

Climate Zone (1–6)

Wall Insulation

Space Type

Saved Rooms

Room	Area (m²)	Occ.	Cooling	Heating	Ventilation	Actions

Load Schedule

Building-level rollup of every saved room, ready to export

Load Schedule

Room	Space Type	Area (m²)	Cooling (kW)	Heating (kW)	Ventilation (L/s)

Psychrometric Chart

Dry-bulb / humidity ratio plot at sea level — plot 2 state points and read the process line

State 1 — Dry Bulb (°C)

State 1 — Relative Humidity (%)

State 2 — Dry Bulb (°C)

State 2 — Relative Humidity (%)

Psychrometric Results

State 1 — Humidity Ratio

—

g/kg dry air

State 1 — Enthalpy

—

kJ/kg

State 2 — Humidity Ratio

—

g/kg dry air

State 2 — Enthalpy

—

kJ/kg

ΔEnthalpy (Total)

—

kJ/kg

Approx. Sensible Heat Ratio

—

Takeoff / Bill of Quantities

Tally duct sheet metal, pipe length by size, and fittings for a quick material estimate

Duct Runs

Shape

Diameter (mm) — if round

Width × Height (mm) — if rect

Length (m)

Shape	Size	Length (m)	Perimeter (m)	Sheet Area (m²)

Pipe Runs

Nominal Size (mm / DN)

Length (m)

DN (mm)	Total Length (m)

Fittings Count

90° Elbows

Tees

Reducers

Dampers

Valves

Summary