Flow-rate and pressure-drop simulator

[@fjrxj1134]

Brilliant John, many thanks for spending the time to posting your simulator, will certainly be using this in the future, many thanks

[@bruceboucher2134]

Hi John, once again some good advice, as you infer some engineers will install by habit not by knowledge. So right to get HP design and installation practice correct. You also talk about consumed energy which all add up to annual running costs.

[@marcozorzi6770]

Great video John! You are a genius 🔝😊

[@heatpump8566]

Fantastic visual this john

[@dkcmechanical]

Top man, thank you very much! 🙌🏾👌🏾💪🏾👊🏾💯😁

[@hussaingonoo8408]

Fantastic video

[@hughrattray9354]

Really useful. Thanks for putting this up. How would you calculate the pump size for a house where the radiators are connected in parallel? Do I just add the pressure drop for each radiator to work out the total pressure drop?

[@johncantor4056]

All radiators would normally be in parallel and the pressure is ideally the same for 1 on or all on. Actually, the pressure drop due to the radiator is very small, it's the pipework and radiator valves that cause most resistance. so, the flow-rate needs to be known, and if for example you had a 5kW Heat pump, then if the total flowrate of about 14lit/min, you get a dt of 5. e.g. 40c in and 35c out. You may also need to ensure that your system will cope with some radiators off (or low flow). So to answer your question... add up the flow-rates. don't add up pressures of parallel circuits, does that make sense?

[@henrybartlett1986]

Wow! This is terrific! Can you do one for commercial pipe?

[@johncantor4056]

Hello Henry, sorry for the delay. This was never designed as a design tool, more a teaching aid to help people learn what happens without having to get a pump, some pipes, a bucket and a stopwatch. There is a good online pressure-drop calculator www.pressure-drop.com/Online-Calculator/ that is probably better for any size.. this also allows for temperures and other finer details

[@robwheaton]

Thanks for sharing John! In terms of locating the heat pump externally I assume closest to system water tank the better in terms of efficiency? Also would the HP perform better on sunny elevations?

[@johncantor4056]

Yes, its probably the hot water (DHW) efficiency that is affected most. Its not ideal having to heat the volume of water in the pipe, and after heating the cylinder, the very hot water can sit there and all heat is lost in time. This very hot water can sometimes dissipate to the radiators afterwards, so not so bad. Re sun. The advantage of a sunny location is less that you might think. The air temperature on sunny and shady sides is usually very similar once its moving. Choice of position is usually made by other practical reasons.

[@aravindsn]

I wanted to simulate for my Heat Pump circulation, which is normally 1.5Bar, 21 PSI. But with your simulation it is only limited to 0.5 Bar. why is it ?

[@johncantor4056]

So, the pressure we are varying here is the difference in pressure across a system. Most circulation pumps will manage about 5m head pressure (yes some are more). this is about 0.5 bar. So, if your system is pressurised to 1.5bar, the circulation pump inlet should be 1.5 bar, and the outlet could be anything up to say 2bar, but you won't know this.. there is no outlet pressure gauge. If your system pressure were low, at say 0.5 bar, then the pump outlet might be 0.5 + 0.5 = 1 bar. The simulator relates to resistance of flow in a system, and in general how small-bore pipes can be a problem, needing excessive pump pressure and pump energy. does that make sense?

[@aravindsn]

@@johncantor4056 Thank you for the clarification, then i can reference here as the difference in the pressure.