RE: Air Con vs. Heat Exchangers

["Kenneth Watt" <kennethwatt@xxxxxxx>]

I can't remember, after that nonsense they got really twitchy about the
systems used, that was in the eighties or early nineties wasn't it? Could
have been both, but I think it was legionnaires now you mention it! I
remember getting a load of bumf in from some government department all
about
the dangers of air-con cooling plants and how they had to be cleaned on a
regular basis if they were certain types of system because at that time we
were agents for a Swiss air-con manufacturer that was making systems
primarily for medical purposes, high filtration etc. After that we bailed
out of this market because the check and legislation made it nigh on
impossible to turn a profit on these systems, plus at the time there was
little volume outside the NHS and very large corporations.

Saying that, from what I heard in the trade the NHS was not paying the
maintenance bills so the firms involved withheld service, shocker! Not! It
was often taking them 6 months + to settle accounts for us and another firm
that was servicing and supplying bags for their cleaners. Needless to say I
do not now do work for the NHS, I run a business not a bank ;o) The NHS
obviously thought they could save some cash on maintenance, but I think
they
now have new guidelines to follow after that fiasco and now H&E looks
at any
air-con system in areas where there is food, I know, though I'm not sure
about just plain office environments.

K.

-----Original Message-----
From: 	Mick Furlong [mailto:dorsai@xxxxxxx]
Sent:	19 May 2001 04:03
To:	ukha_d@xxxxxxx
Subject:	RE: [ukha_d] Air Con vs. Heat Exchangers

Salmonella or legionnaires?

> -----Original Message-----
> From: Kenneth Watt [mailto:kennethwatt@xxxxxxx]
> Sent: 18 May 2001 18:42
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Air Con vs. Heat Exchangers
>
>
> Mark,
>
> There are systems that allow this sort of use of air-con/heating
through
> "blown-air" systems and they are readily available from a
number
> of places.
> Most are designed for commercial appliacations though and, as such,
cost
> packets! This is due to the technicalities of the electronics and
cooling
> power, put it this way, a compressor for a domestic fridge freezer US
size
> is ?200-250 that cools, approx, 8cu ft to -18C and 15cu ft to 3C
> now imagine
> on the same scale the cost to cool a home! It doesn't quite work out
that
> way but you'll see what I'm driving at, it all comes down to scale and
> efficiency of the actual components. BTW, that US fridge/freezer
> retails at
> 1.5K!
>
> K.
>
> -----Original Message-----
> From: Mark Harrison [mailto:Mark.Harrison@xxxxxxx]
> Sent: 18 May 2001 15:17
> To: 'ukha_d@xxxxxxx'
> Subject: RE: [ukha_d] Air Con vs. Heat Exchangers
>
>
> OK - here's the complex one!
>
> This allows three separate modes:
>
> 1: Basic heat exchanging only, to warm incoming air, for ventilation
in a
> fuel-efficient manner.
>
> 2: Heat exchanger bypassed, heat pump cools the incoming air, for
summer
> cooling.
>
> 3: Heat exchanger warming incoming air, then heat pump heating it, for
> winter heating.
>
> For clarity, I've included the "airflow" paths with other
paths greyed out
> for all three modes. As Ian says, it may be possible to consolidate
the
> "exchanged" and "bypass" paths for the _outgoing_
airflow in a domestic
> system.
>
> In principle, there's a fourth mode, which is bypassing the heat
> exchanger,
> but not turning on the heat pump. It would basically be ventilation
only,
> with no heating/cooling. Not sure whether you'd ever end up using
> it except
> in situations where the heat pump was thermostatically controlled and
you
> didn't want it to get any colder indoors!
>
> Mark Harrison
> Head of Systems, eKingfisher
>
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> -----Original Message-----
> From: Mark Harrison [mailto:Mark.Harrison@xxxxxxx]
> Sent: 18 May 2001 11:42
> To: 'ukha_d@xxxxxxx'
> Subject: RE: [ukha_d] Air Con vs. Heat Exchangers
>
>
> OK, here's the next phase.
>
> This has a "heat pump" in series with the "bypass"
air routes. This is on
> the basis that you switch the unit into "exchanger bypass"
mode when you
> want to cool down the incoming air rather than let it be
> pre-warmed, and you
> don't bother cooling pre-warmed air.
>
> Furthermore, this assumes that you only bypass the exchanger when you
want
> to cool the air! A bit naive, perhaps, but wait until the next
stage...
>
> In principle, you can acheive this with a domestic air-con unit with a
> separate fan unit (that would normally hang outside the window)
> as follows:
>
> - The Incoming air vent "outside" gets connected to the
"suck in air from
> the room" input on the A/C
> - The Incoming air vent "room side" gets connected to the
"blow cold air"
> output on the A/C
> - The Outgoing air vent "room side" gets connected to the
"input on the
> separate fan unit" on the A/C
> - The Outgoing air vent "outside" gets connected to the
"output on the
> separate fan unit" on the A/C
>
> In the case of a "single unit with warm air trunk"-type A/C,
then
> realistically you just "t-piece" the trunk in with the
Outgoing
> air vent as
> near as possible to the pump, and rely on the pump to suck through all
the
> air. What you may find, therefore, is that you need a twin-speed
> pump on the
> going in this case, which runs faster when the air-con's on!
>
> The final piece (coming soon), is the bit that I always have to think
hard
> about. It combines the use of this system, with the ability to
"run the
> air-con backwards" and use the "hot air out" on the
aircon to _heat_ the
> rooms...
>
> Mark Harrison
> Head of Systems, eKingfisher
>
> ******************************************************************
> **********
> Kingfisher plc
> Registered Office: North West House, 119 Marylebone Road, London NW1
5PX
> Registered in England, Number 1664812
>
> This e-mail is only intended for the person(s) to whom it is addressed
and
> may contain confidential information.  Unless stated to the contrary,
any
> opinions or comments are personal to the writer and do not represent
the
> official view of the company.  If you have received this e-mail in
error,
> please notify us immediately by reply e-mail and then delete this
message
> from your system.  Please do not copy it or use it for any purposes,
or
> disclose its contents to any other person.  Thank you for your
> co-operation.
> ******************************************************************
> **********
>
>
>
> -----Original Message-----
> From: Mark Harrison [mailto:Mark.Harrison@xxxxxxx]
> Sent: 18 May 2001 11:09
> To: 'ukha_d@xxxxxxx'
> Subject: RE: [ukha_d] Air Con vs. Heat Exchangers
>
>
> > But the Baxi system sadly doesn't allow this, which is why I
haven't
> > done anything to date.
>
> Seems mad that it doesn't! I've got various brochures at home from
other
> companies who provide similar stuff... let me know if you want me
> to dig out
> some other names...
>
> Alternatively, for the price of a four valves and a couple of meters
of
> ducting, you could probably rig up something yourself (see attached.)
I
> would guess that the four valves could be wired in parallel, and run
of a
> single (X-10?) relay...
>
> Mark Harrison
>
>
>
>
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