Articles, Blog

Heat Pump Guide, how to select, compare and efficiency rating hvac

December 6, 2019


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

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21 Comments

  • Reply John Cena November 5, 2018 at 8:02 am

    Nice video, nice explanation.

  • Reply N Eliseo S Carranza November 5, 2018 at 8:09 am

    Was waiting for. Best engineering channel over youtube ever….. thanks you so much…

  • Reply The Engineering Mindset November 5, 2018 at 9:19 am

    ⚠️ Found this video super useful? Buy Paul a coffee to say thanks: ☕

    PayPal: https://www.paypal.me/TheEngineerinMindset

  • Reply Cybertwood November 6, 2018 at 2:17 am

    You forgotten to mention that for an open loop you can also use groundwater

  • Reply Ben Wilkinson November 6, 2018 at 5:50 am

    The American units grind my gears

  • Reply hvac officail November 7, 2018 at 8:56 pm

    Plz make videos on firefighting pumps also

  • Reply Bryan Strausburg November 8, 2018 at 6:13 am

    i wanted to let you know i love all of your videos. keep up the great work for and thank you for what you do!

  • Reply Islam galal November 9, 2018 at 4:34 pm

    hey man , please we need an illustration of FANs Types thank you

  • Reply Philippe Gosselin November 10, 2018 at 11:34 pm

    Good video. But I was wondering; are you sure, in the imperials coefficents, that the top unit you need to use is the BTU and not the BTU/h ? Because the watt is a unit of power like the BTU/h and the BTU is a unit of energy like the joule.

  • Reply bob smith November 19, 2018 at 12:22 am

    What pressures are the refrigerants boiling at that temp?

  • Reply djbutch123 December 20, 2018 at 5:51 pm

    You missed IEER at the end. But great video

  • Reply zubair khan January 2, 2019 at 7:05 am

    Sir please can you tell me dx system and vrf system are close cycle are open cycle.. Please reply

  • Reply Eric Kosak January 19, 2019 at 11:33 pm

    Thank you for your videos.

    Lately, I have been looking at chiller offers from Sanden, Multiaqua, Daikin (Altherma 3), and Chiltrix among others.

    They claim to produce heating, cooling, and hot water (except for Sanden which only produces heat and hot water) at very high levels of efficiency using air to water heat pumps.

    I suspect they all use a reversing valve (except again for Sanden).

    Some of them claim very high COP numbers. They, also, claim lower costs than GSHP.

    When I compare long term ownership costs, I find that their costs are usually greater than air to air in spite of having higher COP numbers. In fact, I tend to get confused in attempting to decide among them.

    Could you cover these types of heat pumps in more detail?

    Could you, also, please provide an industry perspective of where trends in products (cooling, heating, and hot water) and future (not too far) consumer efficiency is going?

    Finally, could you provide a single chart providing 10-year total cost of ownership for different technologies (for instance, air to water, air to air, etc).

  • Reply backpackmac January 25, 2019 at 8:26 pm

    Good video but key elements are scop and capacity drop off at lower temperatures. There is a large variety depending upon specification. Check scop and delivery capacity at -7 degrees ambient with flow temp for heating at 45c to make sure you are getting a decent product

  • Reply The Engineering Mindset March 27, 2019 at 9:17 pm

    Learn HOW HEAT PUMPS WORK here ➡️ https://youtu.be/QykwWs3L1W8

  • Reply Stephen Doherty May 29, 2019 at 12:36 am

    If you can choose between air source and ground source heat pump then whats the return on investment ie which is going to cover its install cost sooner assuming a set amount of use and heat generated. Also would air source heat pumps work best in warm climates where outside air can be very warm (30/90s)? Also many water source heat pumps need access to a PRIVATE water source, not sure you can just extract the heat from your local river and dump the colder thermal load back into the water via a heat exchanger? Also if you live in warmer climates would nighttime air temp not be be quite high and thus allow for air source heat pumps to extract heat even overnight? It also seems quite straightforward to dump the excess heat into a water tank so in the morning your shower is not just luke warm.

  • Reply Bernie OSully July 19, 2019 at 9:45 am

    Very expensive it all cost to much,

  • Reply Balaram Jeppesen August 15, 2019 at 6:19 pm

    Do manufacturers include the energy used for pumping the water/fluid to the heat exchanger into the energy rating?

  • Reply Christopher Stout September 13, 2019 at 3:34 pm

    It would be great to see a video where you go beep into the workings of enthalpy recovery ventalators, and the other versions of balanced ventalation. As well as dehumidifiers!! Hopefully those aren't too building sciencey requests; Great videos, keep it up!!

  • Reply justfly2525 September 17, 2019 at 1:32 am

    Great job… Thank you, I've been looking all over for this kind of information.

  • Reply mimi buckles September 25, 2019 at 11:27 pm

    Fascinating! I'm building a house and a green building consultant recommended a heat pump. I could not understand how it could work and now I get it! Brilliant! I had no idea that there were anti-freezes that would boils at -26.3˚ C and lower temperatures! Thank you so much.

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