On Fri, 24 Jun 2005 21:20:14 +0100, "Doctor Evil"
wrote:



The Takagi condensing multi-points, not available in the UK (yet) are "very"
efficient, and can return around 38 litres/min. Instant water heating has
become the norm in Japan now. It is a case of use low energy and store lots
of hot water taking up space, or use a lot of energy all at once, suing most
of the energy available down your gas pipe. They also developed
multi-points that can be installed outside to save space too.

The T-H1 at over 95% efficient and over 30 litres/min flowrate.
http://www.takagi.com/web2003/pdf/TH1.pdf


You really are a sucker for claims on web sites.

- The so-called 95% efficient is measured on what system? Presumably
a U.S. one? There's an asterisk against the number and they do not say
what the measurement method is. The specs seem to miss out on heat
output to water so one can't even see the story from that.

- If it's the same one as is used in the UK, then I find it very hard
to believe that it is achieving 95% when everything here is achieving
90-91%. If it's the continental European system then the range is
normally in the 106-109% range, and this would be pretty poor.

- Looking at the internal design, the thing has a secondary heat
exchanger and upfiring burner. Hardly leading edge, is it?

- The NG input is 199,000 BTU in deprecated units, or 58kW. This is
virtually the entire output from a domestic supply, leaving no spare
capacity for anything else unless a commercial supply is installed.

- Your claim that it delivers 38lpm is only under the best possible
conditions. This is equivalent to 10 U.S. gallons/min, and from the
graph, this is only achieved for water temperature of 60F (15.5C) in
and 95F (35C) out (hardly hot water is it?) or 70F (21C) in and 105F (
41C) out (tepid). If you look at the rate for a more realistic
figure using the UK defacto standard of dT=35C (8C to 43C) (46F to
109F)then the output is at around 6 US gpm or 23lpm which is not
impressive at all.




--

..andy

To email, substitute .nospam with .gl

The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com