jg167
New Member
A heat pump water heater has a longer recharge time then gas or electric water heaters due to their lower heater capacity (likely not the proper term but the supply of heat). All the tank hot water heaters (i.e. not tankless) I am aware of follow the same design. Hot water is supplied as needed and as the level of the water is drawn down water from the line is used to keep the tank full which of course immediately cools the water in the tank down bringing the heating method online to bring it back up to temp. All this is ongoing as hot water is being used.
Consider another possibility which would be two (A and B) smaller water heaters in tandem with a common control system. Hot water would be taken from A withOUT refilling it with line water until perhaps 90% of its (fully hot) water is gone. Then the active tank is switched to tank B and tank A is filled back up engaging its heat source if not already active. At all times the heating element in each tank monitors the water temp and comes on accordingly (so it has to work even if the tank is only partially full). It is unlikely that tank A when newly refilled with cold line water could be brought up to temperature in the time it would take to drain tank B if at maximum output, so you still could run out. But this seems unlikely and while you had hot water it would be fully hot. Such a design might replace a single 40g unit with two 30g units and use 2/3's of each until the the active unit is swapped . So you would get a full 40g of fully hot water before it suddenly got much cooler instead of perhaps using 20g form a standard unit until you noticed the cool down, especially with a heat pump.
Has anyone heard of such a design? If would of course be more expensive but also offer better functionality.
Consider another possibility which would be two (A and B) smaller water heaters in tandem with a common control system. Hot water would be taken from A withOUT refilling it with line water until perhaps 90% of its (fully hot) water is gone. Then the active tank is switched to tank B and tank A is filled back up engaging its heat source if not already active. At all times the heating element in each tank monitors the water temp and comes on accordingly (so it has to work even if the tank is only partially full). It is unlikely that tank A when newly refilled with cold line water could be brought up to temperature in the time it would take to drain tank B if at maximum output, so you still could run out. But this seems unlikely and while you had hot water it would be fully hot. Such a design might replace a single 40g unit with two 30g units and use 2/3's of each until the the active unit is swapped . So you would get a full 40g of fully hot water before it suddenly got much cooler instead of perhaps using 20g form a standard unit until you noticed the cool down, especially with a heat pump.
Has anyone heard of such a design? If would of course be more expensive but also offer better functionality.
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