(gentle guitar music)
- [Vincent] Hi everyone, I'm gonna show you today
how to use the whole house steady state simulation
and what sort of information you can draw from it
in order to help your understanding of the sort of gains
that we have around our building and how they impact
the internal temperature of your building
over an averaged period of time.
We have all these parameters that you can play with
around here and they'll all alter the building properties
so you can actually see how each of these parameters
is impacting your building and visualise
where the gains might be coming from.
If we're gonna move, for example from summer
to winter, for this particular case we're looking
at summer around Sydney or summer around the Sydney area
so when we move to winter you'd expect
as you expect the sun is low in the sky,
has a lower altitude, angle, during the winter months
or the winter season as opposed to the summer months.
So you can play around with all of these values.
We'll have a look at altering the window to wall ratio
and you'll see that alters your simulation up here
and then you'll also notice that your total
your total internal gains, your total solar gains
from your window will also increase
with your window to wall ratio.
Okay, so let's go through each of these individual
gains and losses that we have in our building.
We have, of course, our internal gains.
Those from people or from equipment or appliances
that you might have within your household.
We have our infiltration losses which
are leakiness in your building so if you have
a high outdoor temperature and a low indoor temperature
you'd expect that any air that leaks into your building
is going to leak warm air into your building
which may be unpreferable.
It depends on what temperature is
and we'll investigate that.
And then you have your solar gains through your window.
Your conduction losses through the window
or conduction gains through the window.
This is just an average for the month so you can see
that in the summer months we have conduction losses
through the window.
That's due to a very high indoor,
very high average indoor temperature
from the incoming sun so that means that we have
a very unpreferable indoor temperature
that is actually losing heat via conduction
on average to the outdoor, to the ambient.
We have our conduction convection losses from the roof
as well which is significantly smaller,
a little bit smaller due to our higher insulation.
You can see the R values up here as well for your roof
so the little subscript r is for your roof,
little subscript w is for wall and wi is for your window
and then you can also see your conduction
conduction losses through the walls, too.
All right, let's have a look at what would happen
with our building if we were to alter
the air change rate in our building.
So at the moment we have a significantly high
infiltration loss in our building in order to net out
the gains that we have within our building
in the summer months so if we were to reduce
that air change rate we'd expect that the internal
the average internal temperature would increase
within this building.
There is no way to lose as much heat out of your building
so you'll notice that your infiltration losses
will decrease but you'll also notice that your conduction
losses will increase.
Your conduction convection losses will increase
in order to average out and conserve energy
within this building over whatever period
of time that you're averaging.
So let's have a look, investigate that.
So we'll decrease our air change rate
and there you have, we've gone from
32 degrees, average indoor temperature
in whatever this average period is
to 42.9 which is extremely unpreferable.
That is a horrendous day to have inside your household.
So let's investigate if we were to then
if this is the air change rate that we have
within our household and this is the indoor average
temperature that we have, what could
we possible do in order to
create a more preferable environment
within our building?
We would first look at our internal gains
or first look at our window to wall ratio
which would be our largest contributor
so you can see that the solar gains here
are at almost two kilowatts so these are the largest
contributor and the only other
next to the internal gains that's actually
producing energy within the building
so it's actually increasing the indoor temperature
of the building.
So amongst these two we need to control either of these.
You may not be able to control internal gains.
It depends on whether you already have really
efficient appliances or how many people you have
occupying your building but you may be able
to control the solar gains within your building.
So currently we don't have any shading on this building
but let's have a look at what we can control
and that's our window to wall ratio.
So if we reduce this window to wall ratio
what we'd expect is that we have a decrease
in the solar gains and that we would have
a decrease of the indoor average temperature.
So let's have a look at that.
All right, excellent so we can see that decreasing
our window to wall ratio has reduced the solar gains
and has reduced our average indoor temperature.
Okay everyone, so you've seen the impact now
of actually changing some of these variables,
your window to wall ratio and how that impacts
the solar gains on your building.
Of course, in summer we can see that we've
reduced our window to wall ratio to the minimum
that we're actually allowed to within the simulation
but what we can see is still we have significant
solar gains that are causing an unpreferable temperature
within our building so what we could implement
is then a shading strategy of some sort
in order to bring our indoor average temperature down
even more so and reduce those solar gains
at this unpreferable time of the year.
I encourage you to go and play around with more
of the variables and just have a look at how
it actually impacts the indoor average
temperature of your building based
on the outdoor average temperature
and use this as a resource throughout your tutorials
to help your understanding of the various
components that come together for your building.
(crescendo music)