Thermal Stores for domestic hot water.

[noname]

For my own general knowledge I would be obliged if someone could answer the following questions regarding thermal stores for domestic hot water. The situation I have in mind is for a 2 bed modern semi. with 1 bathroom and 1 shower room.
1. What minimum capacity thermal store would be required?
2. Would a thermal store with an internal coil be suitable or would one with a plate heat exchanger be necessary?
3. Are plate heat exchangers internal or external to the storage tank and if external are they supplied with the tank or are they an added extra.
4. I understand a pump working in conjunction with a flow switch is needed with a plate heat exchanger. Is this correct?
5. Is there a significant advantage of one type of heat exchanger over the other and is there a significant difference in product and installation costs?
Perhaps I should explain that my daughter's house has a Boilermate 2000 installed and I am guessing that eventually it will need replacing. Having mains pressure hot water with a normal (not a Combi) gas boiler seems to me to have its advantages.

 

[SimonG]

You have given no info with regard to methods of heating the store. Unvented cylinder.

 

[noname]

Sorry. Condensing gas boiler-Glowworm 18i. Vented system

 

[SimonG]

You dont want a thermal store then. Unvented cylinder as long as water pressure and flow is sufficient.

 

[noname]

Am not keen on the idea of an unvented cylinder. Additional hazards I understand. Do unvented cylinder systems have to have an annual inspection or does this only apply to rented properties?

 

[SimonG]

Yep annual service. Cheaper to run the unvented than the thermal store.

 

[Riley]

Plus if it's installed by a competent engineer then you have minimal risk.

 

[Whyme]

Most folk who have the open vent plate type thermal stores utilize solid fuel aswell because you have to keep the store hot constantly or it can't heat the plate for your hot water..more expensive than unvented pal

 

[lame plumber]

for a 2 bed 2 bath hose, stick an electric shower in one bathroom and a combi to supply the other, waste of money doing anything else