Replies to post #24643 on Wanderport Corp (WDRP)

[BeerIsGood]

Excellent analysis.

I didn't consider amount of wattage used as efficiency, but rather as cost to operate. So sounds like the WDRP unit will also be very high efficiency but cost less to operate due to requiring less watts to get the water heated. Now that sounds like a good selling point. Less out of pocket money to take a shower. I like it.

[water boy]

Thank you for sharing, your post explains it really well. Let me add to what you have posted.

Sounds like you talk about heat transfer rate. A resistance heating approach as in a traditional tankless electrical water heater got a limitation of the heating surface area and the heating transfer coefficient.

Electricity--(1)--> Heat at heat exchanger--(2)--> flowing water

Although it could convert electricity into heat at 99%(Step 1), it is still limited by how quickly it could transfer heat energy into the mass of water (Step 2). In order to keep up with higher flow rate, it would have to oversize the heat exchanger and end up consuming more electricity.

Microwave water heater, on the other hand, use two types of heat exchanger per se--1) the water itself 2) proprietary ceramic heat exchanger. Majority of the heat energy has no limiting factor of heating surface like the traditional tankless water heater, because once water absorbs microwave energy its whole water mass becomes heating surface. For the same reason, its size tends to be smaller, since it does not require as much heating surface.

So the reason that Wanderport saves energy is not that they could match the efficiency, but it does not have to compensate the heat transfer coefficient as the existing technology must do, IMHO.