When selecting a brewhouse, there are several different tank configurations available on the market.
A two vessel system consists of a dedicated mash vessel and boil kettle, forgoing a hot liquor tank (HLT) in favor of an on-demand hot water source. This hot water source is supplied to the brewhouse by way of commercial tankless water heaters. This provides an endless supply of sparge or strike water at precise temperatures without the need for an additional tank.
We believe this is an ideal design configuration in contrast to typical 3 vessel or combi-vessel system. Keep in mind that most of those brewhouses don't have dedicated heat sources for their HLT tank. Instead, the brewer must heat the sparge or strike water in the boil kettle, then transfer that fixed water volume to the HLT tank, which is merely an insulated holding tank where sparge water is stored until run-off begins.
This unnecessary 3rd vessel occupies additional space, and time on brew days, and even limits the brewer to a fixed amount of water that can be stored in the HLT.
Instead, we believe space typically reserved for an HLT would be better served by a whirlpool tank, which offers greater flexibility of production capacity.