Swimming pool HP direct 'V' primary/secondary

We have a 70kw HP water heater with a HE to separate the pool water. therefore in order to maintain 28c in the pool the primary needs to be around 40c. HP's are more efficient at lower temps and the client is looking to replace the unit. We recommend a proper pool heater. However my guy reckons a 70kw c/w HE has a different rating to a direct inline Swimming pool HP
He seems to think we'd need to up rate it to an 80+ kw to give equal performance ?
. That seems at odds to what I would naturally consider right especially as a HP unit de-rates the higher the discharge temp goes and a HE takes another chunk of efficiency so my hunch is that a direct 70kw HP should give better performance like for like?
Thoughts inc real world examples welcome :-)

no one..........?

my only experience is with servicing calorex units and the like, so no experience sizing them, i would have thought you were correct though, can you check with plate heat exchange manufacturer to see if any difference between chilled and hot water HE?

How many m3 of water in the pool?
Is it covered when not in use?

What is the pump rate?

thanks but the size and flow isn't the question.

I need to know if a HP+ HE primary& secondary system is more efficient than a standard swimming pool unit . It doesn't make sense..

I can't find any detail on the web sadly

Could you measure the COP of your existing system and compare it to the system you are proposing?

How robust would a swimming pool unit be at dealing with chlorine etc, one advantage of primary/sec is no damage to heat pump HE, the one public pool i work on uses this method, given the staff's eagerness to over dose the pool with various acids it has saved the heat pumps many times over. Are you thinking of just one large unit or a few smaller ones to allow capacity control (and redundancy)

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Originally Posted by al

How robust would a swimming pool unit be at dealing with chlorine etc, one advantage of primary/sec is no damage to heat pump HE, the one public pool i work on uses this method, given the staff's eagerness to over dose the pool with various acids it has saved the heat pumps many times over. Are you thinking of just one large unit or a few smaller ones to allow capacity control (and redundancy)

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swimming pool units have titanium HE's to protect from the water. A single unit is ok as for a large amount of water and no need for really fine temp limits there is no point in capacity control.

Quote:

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Originally Posted by r.bartlett

thanks but the size and flow isn't the question.

I need to know if a HP+ HE primary& secondary system is more efficient than a standard swimming pool unit . It doesn't make sense..

I can't find any detail on the web sadly

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Obviously, any HE between the HP and the pool has losses and to avoid them I suggest you connect it direct to the pool water with flow switch on the incoming water.