Tools for Solar Piping and HVAC Design

Tools for design of solar systems using air as the heat transfer media. 


Tools for sizing ducts and fans.


Pipe flow pressure drop calculator.



See Also:


Pump and Plumbing Sizing for Solar Water/Space Heating Systems
Pump and Plumbing Sizing for Solar Water or Space Heating System

Details on solar pump/pipe sizing...

This page covers the details of sizing the pump and the plumbing for a solar space or water heating system so that the system efficiently transfers heat from the collector to the storage tank without being excessively large.

Details on solar pump/pipe sizing...

How to Determine Collector Flow Rates This page takes you through how to determine flow rate for your collector, and what the tradeoffs are ...
Pipe Flow Calculations


Nice set of calculators for pressure drop, airflow calculations, ...


Free Calc -- a variety of HVAC calculators

Air duct pressure drop calculator...

Pipe pressure drop calculator...


duct pressure lossSome nicely done and generally easy to use calculators for water pipe and air duct pressure losses, channel flow, fan laws, ...

Air Duct Friction Loss Calculator
From The Engineering Toolbox


A simple calculator for calculating the pressure losses in air ducts.  Useful for sizing ducts and fans.
Air Friction chart for flex ducts


An easy to use chart to look up friction losses for flex ducts.

I find this one simple chart answers most of my duct loss questions -- it even has a correction for bends at the bottom.

Flex Duct Loses Due to Compression and Sags...

Static Pressure Losses in
6, 8, and 10 Non-Metallic Flexible Duct...
Flex ducting is subject to extra losses compared to rigid metal ducts when it has sags between supports and when it is not fully stretched out.   These extra losses can be quite larger.
This paper measures extra losses for flex ducting with sags and with compressed ducts.
Stack Effect Ventilation Calculator


Estimates airflow for thermal stacks
Friction loss in round or rectangular ducts ...

Note: The Engineering Toolbox site has a lot of useful stuff, but also has some very scummy popup windows -- so beware.

A very simple air duct pressure loss calculator.

The duct calculator at the link just above is will handle a wider variety of conditions, but is more complex to use.

Temperature Drop Calculator for Air Ducts...


This handy calculator estimates the temperature drop in an insulated duct based on inside and outside temperatures, duct flow, duct size, and insulation level.

Note that the heat loss that goes with this temperature drop is about: (flow in cfm)(Temp drop in F)(1.08) BTU/hr

Air Density Calculator



Calculates air density for the temperature and altitude you input.


Reynolds Number

Re Calculator...

Re calculatorA nice and flexible calculator for Reynodls number -- accepts a wide variety of units and flow conditions.

The fluid viscosity inputs that are needed can be looked up on the Engineering Toolbox website.
Borst Engineering and Construction Calculators

Many Calculators...
Borst Engineering has a whole raft of calculators -- HVAC, solar position, shading, and incident heat, water wheels, pipe sizing, ...
Pipe Flow
Copper Pipe Pressure Drop


Handy pressure drop table for copper pipe.

Note: 1 psi = 2.3 ft of head

Other pressure drop tools on this site:
Engineering Toolbox -- Pipe Flow

Pipe Pressure Drop Online Calculator


Nice online pressure drop calculator.  Handles a wide variety of situations.
Also figures loss for bends, orifices, nozzles, ...
Pipe flow and Duct Flow Calculators

Mike Rocchetti


Calculators for pressure loss in pipes and ducts, steam tables, and a Psychrometric Calculator
Hydronic Heaters -- Baseboard, ...
SlantFin Hydronic Baseboard Radiator Output

Baseboard output at low temps...

SlantFin manual on their hydronic baseboard units showing output at lower temps that might be typical of what you would get on efficient solar heating systems.