Is a pool heat exchanger suitable for a communal heating system?

[LordWest]

Hello all and Merry Christmas,

We are in the process of planning the replacement of our 50-year old heating boiler serving a residential block of 12 flats with a total of 60 radiators. It is a vented single-pipe heating system, which has not been properly maintained, and we only recently installed a commercial magnetic filter to filter out as much sludge as we can prior to the replacement. We will be installing a 100kw boiler. I know that we could also install two 50kw boilers, but this is a matter for a different post. A heat exchanger will protect the new boiler from the old vented system. Our installer suggested that we use the following pool heat exchanger, because it has 2 inch connections matching our 2 inch pipes and also has larger waterways so that it does not get clogged.

POOL HEAT EXCHANGER NORDIC B300 88KW (300KBTU/H)
Pool Heat Exchanger NORDIC B300 88kW (300kBTU/h) - https://nordictec-store.com/b-line-pool-heat-exchangers/171-pool-heat-exchanger-nordic-b300-88kw-300kbtuh.html

How suitable is this pool heat exchanger for our purposes? I am concerned that it may not be as efficient as a normal heat exchanger. Also, the suggested heat exchanger is 88kw, yet the new boiler will be 100kW.

I can order a normal heat exchanger with 2 inch connectors and to address the clogging issue I could use a CMX inline filter like this one here from Addey: MagnaClean CMX® | ADEY - https://www.adey.com/product/magnaclean-cmx The medium and large models can also be used inline.

I would appreciate your feedback.

Below is information for the pool heat exchanger:

POOL HEAT EXCHANGER NORDIC B300 88KW (300KBTU/H): €319.99 VAT included
Pool&Spa Heat Exchanger B300
Nordic Tec B-Serie
Nominal Capacity: 88kW
based on 60 °C difference between heating and heated medium (water to water),
with counter-courent work

Material: Stainless steel 316L
Heat Exchange surface: 0.64 m²
Connections: 2x 2" & 2x 1 1/2"
Important Note: If one of media is glicol, the capacity will be only 85-90% of nominal one
Pool&Spa Heat Exchanger B300

Nordic Tec B-Serie
Technical Details:
Nominal value 88kW (power/capacity) is based on 60 °C difference
between heating water and pool water (calculations are different for other media).
If there is other temperature difference, the capacity is following:
60 °C = 100%
50 °C = 85%
40 °C = 70%
30 °C = 55%
The nominal flowrates values are also required to achieve the declared capacity.

Nominal flowrates: 42/325 l/min (one of opportunities)

Pool Heat Exchanger NORDIC Tec B300 88kW ( 300 kBTU/h )

Swimming pool heat exchanger B300 90 kW- full catalogue of pool heat exchangers by Nordic Tec with quick delivery in every European country.

nordictec-store.com

 

[LordWest]

John,

Happy New Year and many thanks for your analysis. I will enquire about the B3600.

Do you have any views on options 1 and 3 I listed above, compared to B3600 (Option 2)?

 

[John.g]

Option 1, depending on how clean you can get the system is probably a better choice than option 3 despite option 3 having bigger waterways and the ability to split it for cleaning, my experiences of this type (3) of PHE was on a number of ships I sailed on, they needed very careful re assembly with the correct torque settings for the tie bolts etc after cleaning, the rubber gaskets frequently were torn on splitting them and any new gaskets had to be glued on, if you go down this route then who will disassemble, clean and re assemble them properly?.
Option 1, if you are prepared to treat the Hx as a throwaway item should it get plugged is far less trouble IMO but of course may prove very expensive in the long run.
My preference is still option 2.

Of course, as suggested above, by others, you could go for a LLH, with suitable filtration, both magnetic&particle, of the boiler return, you might find that the boiler Hx might last for years and its replacement cost may not exceed and may even be far less than the maintenance cost of either of the PHEs.

 

[LordWest]

ok, many thanks for your reply.