Re: Condensing boilers & microbore pipe

["Simon Rafferty" <simonr@xxxxxxx>]

At its most basic level, a domestic BEMS (Building Energy Management
System) does a few things. Firstly it looks at your boilers cycling. Every
time your boiler calls for heat it fires, this is its cycling. Now if for
instance it calls for heat when the return feed hot water drops below 60oc
for arguements sake it will fire until it just gets above it. What a BEMS
may do is wait until it drops to 55 and will fire untill it gets to say
65oc thus reducing the boilers cycling time. The boiler is most efficiently
burning after the first few seconds of igniting so the longer it burns
continuously the more efficiently it is using fuel. Couple this with an
external temperature sensor which allows the BEMS to compensate for
building heat input (it needs to put less heat into a building to maintain
21oc on a cool day than on a cold day) thus it can work out the most
efficient firing cycle for the boiler based not only on the demand from the
internal thermostats but also from what the whether is doing out of doors.

More expensive systems like TREND can cope and compensate for a thermal
gradient across a building as walls become warmed via sunlight at different
times of day thus inputting varying amounts of heat into different zones,
eg easterly facing rooms may require less heat in the morning and more in
the evening. Beyond this you can link in multiple zoning for heating using
shunt valves and pumps coupled to smart thermostats that set back to a
lower temperature either at night in various zones or when they are not
occupied.

On a domestic scale savings are small 10 - 20% max. But we looked at an
installation in a hotel in Eire that was linked to the booking computer.
The computer booked rooms a floor at a time and reduced the heat to the
floors that were unoccupied. Coupled with a smart thermostat in each room
so that only rooms that were occupied were heated evening and morning time
using solenoid operated valves. This saved the hotel 65% of its heating
bill in the first year and it paid for the BEMS in 11 months !!!!!
For a simple system have a look at Danfoss Randle http://www.danfoss-randall.co.uk/default.asp
this is a boiler management device. If you want to see a full blown BEMS
check out http://www.trend-controls.com/General/English.nsf/Docs/Homepage
we install and commission quite a few of these systems in everything from
football grounds and sports statdia through office blocks and factories.
Next time you go into B&Q warehouse have a look around, they use them
in most of their buildings.

Anyway just my 2 penneth worth

Simon
----- Original Message -----
From: email@xxxxxxx
To: ukha_d@xxxxxxx
Sent: Saturday, November 29, 2003 4:59 PM
Subject: RE: [ukha_d] Condensing boilers & microbore pipe


I suspect the clue is in the paragraph above - Building Energy
Management System.

But what does one of these do, what sort of hardware / software is
required and what would be a ball park figure for domestic
installation???

-----Original Message-----
From: Stuart Grimshaw [mailto:stuart@xxxxxxx]
Sent: 29 November 2003 16:51
To: ukha_d@xxxxxxx
Subject: Re: [ukha_d] Condensing boilers & microbore pipe


On Saturday 29 November 2003 16:34, Simon Rafferty wrote:
> Things that I believe will benefit domestic heating systems much more
in
> the UK is external thermoststs on heating systems combined with
Building
> Energy Management Systems (such as TREND) so that buildings are heated
more
> efficiently.
>
> Even on a domestic boiler, by using a simple BEMS that reduces boiler
> cycling you can make savings of 10 - 15pct quite easily.

What are BEMS Simon?