New technology makes genuine instant hot water a reality

10 August 2015

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The RapidHeat consortium led by Cressall Resistors has developed an on-demand electric water heater that is faster and more compact than other similar products on the market. The EU-funded development project breaks new ground by making hot or boiling water instantaneously available in domestic or commercial applications. Freshly heated instant hot water is not currently available on the market.

Existing hot water taps use a small accumulator of stored near-boiling water to cover the gap before the heating element catches up. The RapidHeat instant water heater dispenses with the need for the accumulator and eliminates the use of stale hot water. This makes the operation more hygienic and also results in water and energy savings for the user.

Peter Duncan, project manager of RapidHeat explains: “The RapidHeat consortium is looking for an industrial partner interested in using the technology in applications like boilers and heaters, hot water taps or hot drink vending machines. We’d like to invite interested companies to contact us and discuss how the technology could enhance their new or existing products.”

The high-tech ceramic used in the RapidHeat water heater boasts high thermal conductivity, which enables high heat transfer at low temperature differences. The material’s high electrical resistivity is comparable to most ceramics, meaning it can be used for the construction of high-voltage heaters of up to 7.2kV.

In addition, the RapidHeat instant water heater has a low thermal mass. These features facilitate full temperature output within 1 second of switch-on, which essentially means instant hot or boiling water can be sourced from any tap equipped with the heater.

The high power density of the RapidHeat product also means the heater is smaller and lighter than other technologies on the market, which makes it suitable for applications where space is limited. Its IP56 rating means the RapidHeat instant water heater is suitable for domestic, automotive, traction and even marine use.

Duncan continues: “Compared to conventional mineral insulated tubular heaters, the RapidHeat high-power liquid heater reunites a series of useful features that exist individually in many materials, but are rarely found together in one technology.

“Cressall Resistors originally developed the technology for its water-cooled EV2 brake resistor, which has been on the market since 2012. As time went by, we started exploring alternative applications for the technology, including using it as a controlled high-power liquid heater.”

The RapidHeat technology is patented in Europe, North America and Asia. Go to to learn more about the on-demand electric water heater.

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