- #1
TSN79
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Consider an underfloor heating system in an apartment building. Each apartment has its own distribution box with a number of loops and a thermostatic mixing valve set to 35°C. The loops are intended to work with a ΔT of 5°C (35-30), and the riser pipe supply temperature is 75°C. Say there are five loops, each with a flow of 2 l/min (0,033 l/s). Using the equation kW = l/s ⋅ 4,18 ⋅ ΔT each loop provides about 0,69 kW. The loops rely on a separate circulator in each distribution box.
I wonder what will happen if each loop's flow rate is doubled to 4 l/min (0,066 l/s). The loop's ΔT will naturally decrease as the water flows faster, but I'm tempted to consider it simply as an exchange where ΔT is halved as the flow is doubled. Am I correct? Does that also mean that the mixing valve will need to receive the same flow of 75°C water from the riser as when the loops had 2 l/min?
I wonder what will happen if each loop's flow rate is doubled to 4 l/min (0,066 l/s). The loop's ΔT will naturally decrease as the water flows faster, but I'm tempted to consider it simply as an exchange where ΔT is halved as the flow is doubled. Am I correct? Does that also mean that the mixing valve will need to receive the same flow of 75°C water from the riser as when the loops had 2 l/min?