Hello,
it's Robert Unsworth.
I'm a refrigeration engineer for GEA. You've
seen me before drawing thermal processes.
I thought I'd do another one,
but this time we'll look at the dairy process.
So we can start by sketching out the process.
Typically the milk comes in
on a truck
from the farms and it's pumped into the process.
We'd like it at plus two degrees Celsius,
but sometimes it warms up either at the farm itself
or
through the transport.
So we have a heat exchanger, the intake chill,
and then the milk then passes on to basically holding tanks,
which are keeping it chilled,
ready for processing to start.
So the milk is then pumped.
There's other things happening,
filtration and different things,
but the milk is pumped into
the pasteuriser
where the milk is
heated up
via steam.
But there's a heat recovery section.
So the hottest milk goes to preheat the milk that's coming in,
like so.
And then when the milk leaves the recovery section,
you know,
the pasteuriser,
it's chilled via refrigeration. And then it goes off to packaging.
Because
we're putting in heat,
we have a heat injection system,
for a better word.
So that would be a steam heat exchanger,
which would then be supplied via a boiler.
So the boiler would be outside in the boiler house and
feeding all the heating requirements for the dairy. And then with regards
to the refrigeration process,
we have a cooling section on the pasteuriser,
which needs refrigerating.
We have the initial intake chill,
where the product goes into the production area.
And of course,
we have the air coolers,
which are keeping the building cool.
So in effect,
the heat is going in via the boiler or via the sun.
And we're removing it again via the refrigeration processes.
So we'll pump glycol around these coolers,
for example, absorbing the heat and taking it back into our refrigeration system.
So therefore, we
need a refrigeration system.
So we'll have a chiller, for example.
The chiller
would do, let's say,
3000 kilowatts worth of cooling to provide the
cooling for the whole process and building.
To provide the 3000 kilowatts,
we would consume around about
600 kilowatts of electricity.
Both get added together.
So we have 3600 kilowatts,
but at 35 degrees,
where it's rejected externally through our cooling tower,
which would be on the roof, for example.
And these use fans and water to reject this
3600 kilowatts worth of heat to the ambient air.
What we're talking about now is applying
heat pumps to drive the heating process.
So what we do is we divert this heat
that we would normally reject at the cooling tower.
And we put it into our heat pump,
which is,
in effect,
just another chiller.
It's just operating at a higher temperature.
Boosting it up to a temperature that we can use in the dairy,
say
85 degrees,
we would consume a further,
well,
if we've got 3600 kilowatts,
a further 750 kilowatts would get us to 85 degrees.
So then we have hot water at 85 degrees Celsius.
We can add the 750 kilowatts onto the 3600 kilowatts.
So now we have 4350 kilowatts of heat at 85 degrees.
This 85 degrees, we
pump
back into the dairy and, for example,
put into the pasteuriser.
So we would inject into the pasteuriser.
That would mean that we would make the pasteurising loop,
which is typically around 76 degrees on fresh milk.
That would obviously then switch the boiler off.
We don't need the cooling tower or boiler anymore.
And in effect,
the heat that we put in by heating the product is the same
amount of heat that we remove again at the refrigeration process.
Yeah, it's just a different temperature.
We can provide all heat in the dairy using this principle.
And rather than burning a fossil fuel through the boiler,
if we drove the heat pump with
sustainable electricity from a wind pump,
for example,
you're converting 4350 kilowatts heat derived from a
fossil fuel with a carbon footprint to zero carbon heat.
And therefore it's much more sustainable.
So remember,
a kilowatt of heat is a kilowatt of heat irrespective of temperature,
whether it's zero degrees or it's 100 degrees C.
It's all energy.
And you can provide the heat via a boiler
and burn a fossil fuel in doing so.
Or you can provide it efficiently via a heat pump.
You've got it already.
It's just not at the right temperature.
The running costs will be far cheaper and obviously
much less carbon.
Get us involved earlier in the process before you've
bought your boiler so that we can use the heat
effectively coming from the refrigeration system.
Thank you for your time.
