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Heat Pump Guide, how to select, compare and efficiency rating hvac - YouTube
Channel: The Engineering Mindset
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Hey there guys.
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Paul here from theengineeringmindset.com.
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In this video we're going
to be discussing heat pumps
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and comparing the different
options available.
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Coming up, why heat pumps are efficient,
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choosing an air, ground
or water source heat pump
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and also comparing the efficiency ratings
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such as COP, SCOP, EER, SEER and HSPF.
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Just Before we jump in
I want to take a moment
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to thank Danfoss for
sponsoring this video.
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Danfoss has everything you need
to make sure your heat pump
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is running at maximum efficiency,
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regardless of what kind it is.
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They've put together a
collection of resources
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on their website to help guide
you to the right decisions
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about heat pumps.
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Just click the link in the
video description below
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to access free business
cases, case stories, e lessons
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and even some fun diagrams
similar to ones you see
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on this channel.
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Now, in the last video we looked at the
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different types of heat pumps
and how each type worked.
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In this video, we're
going to be looking at
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how to select one and how to compare
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the different types of heat pumps.
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Why are heat pumps efficient?
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If we look at conventional
heating methods,
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a gas boiler or furnace has
an efficiency of say 85%.
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So, to provide 10,000
kilowatt hours of heating
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over heating season then we need to input
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11,765 kilowatt hours of energy from gas.
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That's because we need to combust fuel
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and then try to capture
any heat it produces
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before it leaves and enters the flue.
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Inevitably, we cannot capture all of it
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so some of it will go to waste.
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An electrical heater is 100% efficient
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so to provide 10,000
kilowatt hours of heating,
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we need 10,000 kilowatt
hours of electricity.
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For this, we're turning electricity
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directly into heat through resistance.
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We can't get more heat out
than the energy we put in
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so we can only get 10,000
kilowatt hours out.
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An air-source heat pump
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is maybe 400% efficient in comparison
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i.e. it has a COP of four.
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We'll see what that means
later on in this video.
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So, to provide 10,000
kilowatt hours of heating
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then we need to input 2,500
kilowatts of electricity.
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Sounds pretty magical, right?
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Well, there's no such thing as magic.
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What that means is we will use
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one kilowatt hour of
electricity to capture
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three kilowatt hours of heat
from the outside ambient air
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and this will produce the four
kilowatt hours of heating.
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The electricity is used by the compressor
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to send refrigerant around the system
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and capture the heat from
outside and bring it inside.
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It can do this because the refrigerant
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has an extremely low boiling point.
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For example, water boils at
around a hundred degrees Celsius
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or 212 degrees Fahrenheit
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and as it boils it carries
heat away as steam.
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Refrigerants have a much
lower boiling point.
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For example R134a boils
at -26.3 degrees Celsius
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and R410a boils at -48.5 degree Celsius.
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So, even when the
outside air is very cold,
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we can still capture enough energy
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to cause the refrigerant
to boil and as it boils
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it carries its thermal energy
away and into the building.
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Obviously the warmer the outside air is
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then the more thermal
energy there is to capture.
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As the outside air temperature drops,
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it will reach a certain point
where it becomes uneconomical
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for cost of electricity consumption
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to capture the thermal energy.
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So, which heat pump should we get?
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Well, first we need to
decide if we want to provide
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hot water or hot air to the property.
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If air then do we also
want to provide cooling
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during the summer?
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Do we have access to a lake or river?
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If not that we can't use
a water source heat pump.
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Will the heat pump be installed
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into a new or existing property?
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If it's existing then
we probably also need
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to install larger radiators
or underfloor heating
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to maximize the heat as
it is a lower temperature
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than conventional boilers.
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We also need to consider our budget
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as the cost can really vary by the type.
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Finally, we can then decide if
an air source, ground source
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or water source heat pump is best for us.
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Air source, air source is
the quickest and easiest
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to install and it looks like a
normal air conditioning unit.
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You can use these units to
generate hot water or hot air.
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Some units also incorporate
a reversing valve
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to operate in a cooling mode also.
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We've covered how reversing valves work
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in our previous video.
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Do check that out.
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Links are in the video description below.
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So, the units are installed
outside and keep in mind
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that it will create
some noise from the fans
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and the compressors.
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They need access to ambient
air so don't box them in,
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else this will cause recirculation
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and you'll be trying to
extract energy from the air
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that you've just extracted energy from.
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This is obviously not very
efficient and it's going to waste
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a lot of electricity.
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Now, these units are
the cheapest to install
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where they're typically
the least efficient
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because air has a low
density and heating capacity
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compared to soil or water.
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Approximate cost to install
an air source heat pump system
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something in the range
of seven to $11,000,
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six to 8,000 pounds or
seven to 9,000 euros.
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This is going to dramatically vary
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depending on the location,
complexity and size.
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Ground source, ground
source is the second most
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popular option, it's more commonly used
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for hot water production.
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You can get units and
systems that can reverse
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to provide cooling.
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It uses thermal energy
embedded within the ground
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where it comes from the sun.
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This option is typically more
efficient than air source
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because the ground has a higher
density and heat capacity
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compared to air.
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This option requires
extensive excavation, however
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so it's best suited to new
builds and can be incorporated
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within the construction to reduce costs.
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The horizontal type uses
pipes buried in the ground
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at one to two meters or three to six feet.
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You'll typically be able to
extract around 10 to 30 watts
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per meter of pipe depending
on the ground type.
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Install costs are typically
somewhere around 13 to $24,000,
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10 to 18,000 pounds or 12 to 20,000 euros
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but this will dramatically
very on location,
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complexity and size.
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If you don't have access to a lot of land
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then we also have the vertical type
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which uses a loop of pipe
placed deep in vertical holes.
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The holes are typically somewhere
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between 15 and 150 meters
deep or 50 and 492 feet
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and you can typically extract
10 to 50 watts per meter,
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depending on the ground
type and the water content.
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Installation costs are
typically 18 to $32,000,
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14 to 24,000 pounds or 16 to 27,000 euros.
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Again, this dramatically
varies depending on location,
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complexity and size.
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Water source, the third option we have
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is the water source heat pump.
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This is the least most common type,
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simply because the property
needs to have access
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to a lake or river.
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Unfortunately, a little garden pond
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just isn't going to be big enough.
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For this type there are two options,
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either open or closed loop.
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Closed loop uses a water
plus antifreeze mixture
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to cycle around and capture the heat.
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Alternatively, we have an
open type which pulls in water
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from the source, extracts the energy
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and then releases this
water back into the source
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some distance away.
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This type usually has much
stricter permissions required
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from the local authority.
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Consider that if the system leaks
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and the refrigerant or
the antifreeze mixture
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gets into the water source,
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it's going to be toxic for the wildlife.
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You might even receive a fine
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from the Environmental Protection Agency.
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It's pretty rare for it to leak
though but it has happened.
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However, this option is very efficient,
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more so than air or ground source.
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The pipes are constantly
surrounded by water
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and the current and flow of water
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means that the energy source
is constantly replenished.
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It's also fairly easy to install
and much cheaper to install
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than ground source.
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Typically, a water source unit can provide
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around 20 to 60 watts per
square meter of water surface.
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Cost to install typically
around 10 to $15,000,
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eight to 12,000 pounds
and nine to 14,000 euros.
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Again, dramatically varying with location,
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complexity and size.
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Comparing different units
and their efficiencies,
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there are many standards
used across the world
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for assessing the
efficiency of heat pumps.
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I'm going to just cover a
few of the most common ones,
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focusing on units made
in the US and the EU.
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COP, COP values or the
coefficient of performance
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is used worldwide for
both heating and cooling.
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It's simply the heating or cooling output
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divided by the electricity input.
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It's not a good indicator
of efficiency, however
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because it only gives a snapshot
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of how a unit should perform
under very precise conditions.
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For example, this unit
has a heating COP of 2.9
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but when you read the small print,
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that was achieved when the outside air
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was minus three degrees Celsius dry bulb
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and minus four degrees Celsius wet bulb
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while providing 35 degree Celsius water
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for 8.3 kilowatts of heating
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and consuming 2.86
kilowatts of electricity.
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As the outside air temperature
varies hourly and daily,
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this is not a good
indicator of efficiency.
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We reviewed the manufacturer literature
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of many air source units
and found them to vary
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between 2.75 and 6.13.
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SCOP or seasonal
coefficient of performance.
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You'll see this on
European units to measure
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the average heating efficiency.
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It's a much better
indicator than just the COP.
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The manufacturer has
to test the performance
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of their units at different
outside air temperatures.
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The unit is expected to operate
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at a specified number of hours
at each temperature per year
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depending on where in Europe it's located.
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There are three zones,
warm, average and cold.
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The heat supplied and electricity consumed
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for the specified operating
hours at each temperature
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is accumulated and divided
to give an average COP
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for the year.
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The SCOP also considers
the energy consumption
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for things such as standby
mode and crank case heating.
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You'll see stickers like this
on the EU produced heat pumps
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which lets the buyer
quickly and easily see
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how well the unit is predicted to perform,
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depending on which climate they're in.
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We reviewed a number of air source units
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for domestic purposes and found
that the typical SCOP values
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lay between 3.9 and 5.2
with a higher number
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meaning more efficient.
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EER or energy efficiency ratio.
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This is a measurement of
a units cooling efficiency
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that's mostly used in the US.
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It's a ratio of a units
cooling capacity and BTUs
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divided by the watts
consumed to produce it.
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This is only tested at one condition,
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generally 95 degrees Fahrenheit
outside air temperature
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and has a return inside air temperature
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of 80 degrees Fahrenheit
at 50% relative humidity.
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So, it's not recommended
to use this to estimate
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your annual energy consumption
or assess how the unit
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will perform in your location
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unless you live in a hot climate.
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However, it is a good way to compare units
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by different manufacturers
for peak summer load.
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From the unit's we reviewed,
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we found units rated between 11 and 16
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where a higher the number,
the more efficient it is.
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The SEER or seasonal
energy efficiency ratio
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is used in the US and the
EU on units which operate
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in cooling mode.
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Manufacturers will calculate
their unit's SEER value
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by testing it at a number of
different outdoor temperatures
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to represent a cooling season.
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The units of measurement
are different with EU models
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calculated on watts of cooling
per watts of electricity
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and US models calculated
on BTUs of cooling
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per watts of electricity used.
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In both cases this is
suitable for units installed
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in very average climates.
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If the unit is installed
in a hotter or cooler part
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of the US or EU then it will
not accurately represent
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how the unit will perform.
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So, it's a good way to
compare different units
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but not a good way to calculate
the energy consumption
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unless you live in an area
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with pretty average weather conditions.
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Typically, you can find
SEER values for US units
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between 14 and 24 and EU
units between 5.25 and 7.2,
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the higher the number, the more
efficient the unit is rated.
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HSPF or heating seasonal
performance factor.
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This is used in the US
for the heating mode
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of air source heat pumps.
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It is the ratio between
heat output in BTUs
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over a heating season divided by how many
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watt hours of electricity
we use to produce it.
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It also takes into account
supplementary electric heating.
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Manufacturers calculate the
unit's HSPF from testing it
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at defined different temperatures
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to represent a heating season.
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This is an estimate of
how the unit will perform
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and it may not actually
perform like this in reality,
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especially if the unit is oversized.
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It is a good way though to
compare different units.
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Typically, a unit would
be between 7.7 and 14
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where the higher the number,
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the more efficient the unit is rated.
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I just want to thank Danfoss again
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for sponsoring this video.
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Don't forget to check out
their heat pump solutions
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by clicking on the link in
the video description below.
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Okay guys, that's it for this video
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but if you want to continue your learning
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then check out these videos
and I'll catch you there
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for the next lesson.
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Leave your questions in
the comments section below
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and don't forget to follow
us on Facebook, Instagram,
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Twitter as well as
theengineeringmindset.com.
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Once again, thanks for watching.
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