You didn't mention *why* it's more efficient! It's more efficient because it's all about the refrigerant loosing too much energy into the large volume of water and thus needing to be heated up even more by the radiator/compressor before the phase change occurs which is just wasted energy, modern high efficiency refrigeration systems (and other industrial processes) are all about optimizing the system to always stay around those phase change regions as pretty much all of the energy transfer in a refrigeration system is from the phase change of the refrigerant hence why heat pipes in heatsinks also have a 'narrow' range of operating temperatures and heat loads for optimal thermal conductivity.

Have to say, I'm enjoying this new PoolBlog channel. Can't afford my own pool, and I live in England, so I'll watch Dave talk about them. Can't wait until he shows us how to deal with leaves and sand in the bottom of the pool.

Lemme tell you the funny story 😁. When I just moved in into my house in Phoenix. I cranked up my natural gas pool heater (~150k kW), cause I wanted to celebrate it and party during Christmas and New Year's holidays. I heated up 15k gal pool almost up to a hot tub levels ~35C, while there was -3C temp outside. I kept it running for a few weeks, and we spent WONDERFUL holidays! Until I received my next gas bill, i realized that our pool party just cost 2k US dollars 🤣. I never ever used my gas pool heater again since then 🤣

Pipe dream of mine has been to have one massive heat pump that moves heat for everything in the house. Moving the heat out of the house into the pool and hot water tank in the summertime, and then moving the heat back in from the pool/ground in the winter.

You pump some amount of heat at some rate. If you receive it at 60l/min you get 3C difference. If you receive it at 6x 60l/m you get 3C/6 difference, almost linearly. As basic as in Ohm's law. Yet still it's the same amount of heat received by water.

In the next video, we want to see Dave floating in the pool with an umbrella drink.

It sounds like what you have is the best compromise. But I would take the sticker off on top of the heat pump. It will not look good in a year and when you remove it then, you will still see the outline of it, because the paint was protected by the sticker from the giant fireball in the sky. Something personally I want to see is, is how the plants overgrow everything in a couple of years and how it looks. Now it looks a bit bare - obviously.

Can someone tell me the difference between heating 300l for 0.6 degrees and heating 60l for 3 degrees. I don’t see the it.

Nice demonstration video.

Yes very interesting Dave about the heat pump

Thanks Dave my Madimack just stopped working. Luckily it is just a flimsy reed switch connected to a paddle they use as the flow sensor, just inside the outlet. Kept throwing E3 error for no reason. Just superglued the magnet back onto the paddle and it works again. While trying to find a fix, I found your video and my flow is way to high and have dialled it back 🙌

Does weather impact the 3* differential calibration?

Enjoy Saturday's forecast temperature of 44 degrees Celsius for Sydney... I have colleagues who are moving office at Parramatta, so I hope their A/C works in their new building! You sure picked the PERFECT day to get your Pool installed... 😁👌

Neat system and explanation. I was wondering if the value the pool has added to your house covers the installation cost?

You can calculate the COP of your heat pump easily if it doesn’t tell you on the display… Take the temperature difference between input and output (3 degrees here) and the water flow in litres/second (1l/s here, ie 60 l/minute) and multiply by 4.2 (specific heat capacity of water in kJ/kg). So your heat pump is making around 1x3x4.2 = 12.6 kW of heat. Now check the power consumption - hopefully much less!!

This also true for airconditioning? What's the discharge air temp vs ambient air temp differential?

could you repurpose the cold side for the house cooling?

Does the outgoing temperature differential remain the same regardless of the desired set point? That is: if you set it to heat the pool to 27 degrees and the heat pump has a +3 degree differential, will it output water at 29 degrees if the incoming water is 26?

Is that a ground or air source heat pump?

Are those valves really mixing valves, or ball valves with two outputs? Whats the actual flow in the system after setting the valves?

Learnt something new today, now I know how to tweak the efficiency :) Also, I recommend basic (KISS) G2 zodiac cleaner, they are really good. Oh and... don't forget the deep return valve in the box, it'll also be a little more efficient.

Wouldn't a flow rate gauge on the inlet pipe be helpful?

what do you do with the heatpump cold side? house AC?

Instead of bypassing part of the water flow, I wonder about just choking the output flow of the filtering pump? Because the filtering pump in spite of being fixed speed, is based on an impeller, meaning it can be choked, and the motor instead of pulling more amps, the opposite will happen. There is only so much you can choke however, because at a certain point there is cavitation in the impeller, causing water to boil and damage the pump.

you wait until it’s hot and the heat pump is belching out freezing cold air and you wished you could duct that into the house😂

FYI, I believe this heatpump is a rebrand of the Mr. Silent, Aqua Forte or AQS. The controller is a standard Tuya jobbie. Advantage is that hooking into the wifi capabilities and controlling/capturing data is easier since it's just a generic-ish controller.

This is just thermodynamics Dave. More flow rate at the same heat input results in lower delta T but the same input in energy to the pool.

It is interesting you'd bring this up, since my dad and I have been having a debate on the flow rate we should use for a solar panel pool heater he built using 3/4" copper pipe. It was my opinion that quantity of heat would remain the same regardless of flow rate. My dad on the other hand was basing his thoughts on temperature differential, which would require a slower flow rate. After all, the goal is increase in heat, which is temp differential times quantity of water heated. 9 hrs? That's an awful lot of time to only rise the temp by 3C. You probably could lose all that overnight when the pool pump is shut off, thus never getting your pool temp to where you want it at the times of the day you'd want to swim, especially on colder days. I was going to experiment and test how much heat I would actually generate at different flow rates: Take a 4L (really 1 gallon around here in the US) container, time how long it takes to fill it, and measure its temperature (heater output temp) compared to pool temp (inlet temperature). Really i don't think his solar panel really does much, just too much pool and not enough heat from the home-made panel. He used to have a pool solar heating system on the roof, but had to remove it in favor of electric solar. We even used it to cool the pool down when it naturally got too hot by running the pool pump at night. Which then has me think of how efficient are HVAC heat pumps really? They deal with air as the fluid medium, which I would think has a slower heat transfer rate. Those things have to raise temperatures a heck of a lot faster than just 3C in 9 hours!

Ok I found how they work. Next Q: can the exhaust cold air be used to cool your beer? Is there an optimum fan speed to do this?

Shame they don't have a built in automatic flow control valve, so it can modulate it's self

How did you establish the flow rate? Just thought it might be nice to have a flow rate meter there on the back of the pump 😊

Basic question: where does the heat get pumped *from*, and how?

4:20 yeah, right. Where does the energy go then? It doesn't just evaporate into the aether. Of course the measured temperature would be lower, a given quantity of water would have less time to contact the heating element. Doesn't mean that the heat didn't enter the water.

No coils of pipe on the roof as a solar collector?

Is a heat pump running on solar more or less efficient than a traditional rooftop pool solar system?

Is the NSW heat wave heading your way Dave? Pool will be handy

I don't get it why lower differential of in and out would make any difference. Pump is either making heat exchanger colder or hotter at constant rate, why would the difference matter ?

Be interesting to see the running costs of this.

I guess I'm confused. Why would you heat your pool during the summer? Wouldn't you want the water to be as cool as possible (within reason)?

Kiwis would use it in winter without a heat pump. :)

So now come the debate, which automatic pool cleaner, and remember they are all based on the original Kreepy Krawly, which was invented in South Africa, but saw the most sales in Australia.

Most of the heat introduced from the heat will be at the heat pumps saturated tempature for the pressure of the condenser, by slightly lowering the average water temperature. You will lower the heat pump evaporator saturated tempature by having a smaller delta you will make the system more efficient. Being a varible capacity inverter unit it should be able to adjust the compresor to make they system run at peak efficiency. Most likely the flow specs are due to fluid flow through the heat exchager being as small as that unit is. I would recommend running it off a second pump to keep it in the desired range and not restrict your main flow.

I don't understand the idea behind it ... The water pump runs at full throttle anyway and uses electricity. If the heat pump gets more water, the temperature delta will decrease, *but the COP will definitely increase*. btw: The current “calibration” will change as the sand filter becomes clogged. Is the heat pump always in operation when the filter pump is on? If not, automatically switchable valves would be worth considering to remove this resistance from the filter.

So when it's being ineficent, where is the 11kw going?

I must be missing something, a 1/2 C temp increase at 360 liters/min is exactly the same amount of heat going into the water as a 3 C increase at 60 liters/min. No difference in efficiency.

Dave, is your pool chlorinated? Brominated? Salt? When are you going to send out a channel notice about the grand opening? 😂🥳

It doesn't matter how much water is passing through the pool heater. If you are running the 60l flow or 100l flow the unit is still putting the exact same amount of heat into the water. If you goal is to have a 3* temperature rise on the outlet then you need to have the lower flow rate. At higher flow rates the temp difference will drop but you are putting the same amount of BTUs into the water but spread out over more volume of water. Your argument is like the car guys saying that having a highflow water pump doesn't cool as well because the water doesn't stay in the radiator long enough to cool the water.... Course here in TX we are wanting pool coolers as they get too hot to use in the summer. Usually people will have an ice company deliver a load of ice to dump in it if they are having friends over.

Apparently Sydney is due for a 42C heatwave this Saturday, so you might want to run your heat pump in reverse! 😂

Dave, what are you doing? So as far as i understood, dave has decreased his efficiency of the heat pump Of course the heat exchanger generates fewer temperature rise if you pump 6 times the volume through the heat exchanger, but this increases the efficiency because you need not that high temperatures You have now a higher temperature(with worse efficency) at the heat pump output and mix it again with the unheated water and get a lower temperature again but you dont see it because theres no sensor Will the heat exchanger gets a damage from the too high flow - i dont know - thats the only point which would support your voodo "CALIBRATION" Will your plastic valves will survive this constant switching - i dont believe so

almost correct dave, but you (and/or your pool guy) is wrong on the reason whay this unit need 65L/min. the problem is that a heat pump will only work better the more water you give it but at some point the relativly small heat extchanger in the unit is simply too restrictive to deal with the full pump capacity of your circulation pump. with a delta T of 3 you are already walking the line of getting the maximum out of the heat exachnger you can reasonly expect. increasing the flow rate would have no meaningful efficiency gains. if you give it 6x the water rate it would still move 11kW into the water regardless but the (water) pump losses are quite large. the heat pump itself LOVES it, but everything else in your system would not.

I think it is better to move 360 it helps with cleaning the water.

2:00 how many already claimed Dave's madmack QR code offer?

To be fair from all I have read your heat pump is also somewhat undersized.... you wouldn't be that far off with the 12kw version and probably could match the flow rate with an inverter pump, and control it such that during heating it runs at the lower speed and only runs at the higher speed during certain periods for cleaning/water turnover reasons. Just eyeballing it your have around a 40k liter pool which is at the upper end of this unit... thankfully more inverter heat pumps are being sold so you can oversize the unit somewhat and widen the efficiency range significantly. I think its an area where state of the art is definitely moving in the last few years... a few years ago nobody would have even sold anything more than an OFF/ON heat pump even though though and oversized unit running at 25% is a lot more efficient than a unit running at 100% outupt this is also in part because in addition to matching your coolant flow, the available heat or heat capacity in the air also varies with climate, and the inverter unit can match that better also... I don't think any of them actively try to hit an optimal efficiency point yet though.

My friends recently bought a new bosch tumble dryer fitted with a heat pump, it's absolute wankery! It takes about 4 hours to dry a few pairs of trousers.

The difference in efficiency outside of the optimum flow rate is minimal, you've just proved that yourself if you think about it..... You can raise all the water by 0.5c or 1/6 of the water by 3c. Then you blend that 1/6 back with the other 5/6 that hasn't been heated at all and guess what, you've raised all the water by 0.5c.... The biggest factor is the difference between air and water temperature rather than water temperature differential across the heat pump. Probably less of a problem in Sydney than here in the UK where the air is pretty much always colder than the water!

We’ve had heat pumps for decades. My fridge/freezer has a heat pump in it. No one ever thinks twice over those.

I need a heat pump to cool the pool.

And the concrete base under the heatpump has a broken corner already. tss tss tss 😀

It's insane that the "baby" heat pump draws almost 50 amps.

When you need to put out a minimum number of videos so you can declare your new pool a business expense eligible for a tax rebate. :D JK, it's all good, we share something and maybe learn a thing or three.

To all those nerding with the math details and trying to finesse the best energy transfer rate: The heat pump is just too small. Why? Because Dave wants to run it off his solar panels' excess power when the house / car is not using it to the their full capacity. Not taken into account is the cooling of the water from conduction (through the pool's concrete body to earth), radiation from the surface to the ambient air (cool in winter) and evaporative cooling to the air (due to breeze / wind). Essentially of those heat losses exceed the capacity of the small heat pump (regardless of how efficient it may be) the pool water will cool and not be comfortable in the cooler months. I doubt anyone will bee using the pool in those cooler months. Also note that this heat pump uses about the same amount of electric power as the pool pump which looks like between 1 - HP (i.e. 750 - 1500 Watts)

How do they calculate the efficiency? 1. If you have a 750 Watt water pump and the heatpump is using 490 Watt for heating, then the efficiency is very low, but it is cooling the heat exchanger very fast, so that you have nearly no heat difference. 2. But if you would reduce now the power of the water pump to 200 Watt, then the heat difference is a bit higher, but the used value used energy per kWh of heat is higher. There is a optimum point somewhere between water-pump-energy + heatpump-energy compared to generated heat. So there is a way to reduce the power of the water pump and this increase the efficiency. To reduce the flow rate with this valves, this is doing nothing. Dave, you can set this valves to fully open, so that the flow rate is the maximum. If you do not change the power consumption of the pump, the efficiency does not change ... or better say, if you waste the water flow with this valves, then you reduce the efficiency. I would add a energy monitoring to the heatpump. I think it tries to create a heat difference of the input and output water. I think the installation company had created a own system to use a unregulated pump and deal somehow with the waterflow-efficiency-thing what they had found in the documents. But it does not work this way. Possibly they have explained to you very convincing, but it is not right in the way they have realized it. Possibly they do not know how to realize it, because they have no electronic expert in their team, only plumber.

Too complicated, just wear a jumper and some socks if it's cold.

17% Heat Pump flow rate, but 100% Filtration flow rate...

Earlier and some of todays cheaper pool heatpumps show the coolant pressure of the condenser (high pressure side) and you are supposed to regulate the waterflow to obtain the ideal condition for the heatpump. The higher the waterflow the more heat you will draw (you'll cool the condenser too much) which will lower the pressure on the condenser side. If the pressure is too low or to high your heatpump will work outside of its ideal conditions and be less efficient. Most bypass setups I have seen or used consist of 3 normal valves (one input, one output and a bypass) or a single 3 way valve (sometimes a output valve is added on the pump to be able to completely isolate the pump for servicing). In your case there are two 3 way valves which can be interesting but also "tricky" to use since you probably have to set both valves symmetrically to avoid "chocking" your pump. PS : if you max the flow to your heatpump you will think that it's not working anymore at all but in fact it is still working only it is heating a huge amount of water less efficiently and the temperature delta is very low and might not be "visible".

it doesn't matter loss in == loss out unless the casing gets hot .. this all makes no sense to an aquarium owner ...

i don't agree with the logic presented .. if the heat pump adds 4kw @60l/hr with a 3 degree rise, or 4kw @600 l/hr with a .3 degree rise.. is the same amount of heat added to the pool's fixed volume 30,000 l. just like wattage for resistors 100 v @ 1 amp is 100 watts, just like 10 v @ 10 amps is 100 wats

Destination F’d!!!

er, tell me you know nothing about thermodynamics without telling me you know nothing about thermo-dynamics ;-) Heat transfer by a fluid is governed by three factors: 1) the fluids specific heat capacity, which for pure water is around 4.2 kJ per Kelvin per kg ie it 1 kg of water will be warmed up by exactly 1 kelvin if you put into it 4.2 kJ 2) The mass flow of the fluid (mDot) this should be obvious from 1), ie the more kg of fluid you flow in any given time period, the more heat you move 3) The temperature difference, again, this should be obvious from 1) that a fixed mass of fluid up by 2degC takes twice as much energy as warming it up by 1 degC If we assume for a second you heat pump has a fixed heat output (it doesn't, but we'll come to that in a bit) then as you increase the secondary flow rate the temperature difference MUST reduce. This DOES NOT mean less heat is being carried, simply you are trading deltaT with mass flow. More mass, less deltaT, less massflow, more deltaT Now, like for all heat engines, for a heat pump which uses a phase change method to move heat the "wrong way" ie against a thermal gradient, we have a fundamental physical characteristic that governs how efficiently it can do that (The carnot efficiency). The efficiency with which it can move heat is INVERSELY PROPORTIONALl to the magnitude of the thermal gradient across which it is moving that heat. What this means is a heat pump has max efficiency at min deltaT, effectively in laypersons terms this is because it is "pushing the heat against the smallest temperature gradient". The practical embodyment of this characteristic is that your heat pump will move the most heat with the least input power at the lowest deltaT achievable So, in reality, you really want your mass flow to be infinite, ie there to be NO deltaT, ie your heat pump output temperature is the same as its input temperature. This is obviously not practical, and in a real system the thermal gradient across the interface boundary (ie across the plates of the heat exchanger that keep the differing fluids apart) is clearly none zero as well. To work out what the best secondary mass flow actually is, and it's almost certainly a significantly higher than the recomended flow range, you actually have to measure the total system energy consumption including the pumping elements! If we consider a pool in a 25degC ambient, were we want a 30degC average pool temperature, and with two secondary mass flow rates for the pool water, a "low flow" which gives a heat exchanger output temp of say 35degC and a "high flow" option that results in a 32degC output temperature in order to keep the pool at our average. The theoretical CoP is set by the absolute temperature difference between the heat pumps input and output fluids and we must work in Kelvin (0 degC = 273 kelvin) Case 1, low flow CoP = (35+273) / ((35+273)-(25+273)) = 31 Case 2, high flow CoP = (33+273) / ((33+273)-(25+273)) = 38 Here, because the deltaT's are so small, we are into a range where the inverse nature of the division inherent in the Carnot efficiency calculation makes large differences to the CoP for small differences in the deltaT. In a real system we will not be quite as "high gain" as this, because we have those temperature gradients intrinsic to the heat exchanger itself, ie we actually have to push the heat across the boundary between the two fluids. Add in a practical 3degC heat exchanger boundary graident and those CoPs fall to 19 and 22 respectively. You heat pumps maximum CoP (claimed to be around 14) will be developed at the lowest possible secondary deltaT, and probably at it's lowest rated power. This claimed max CoP obviously includes all the other "in-efficencies" and losses" ie driving the cooling fan etc So why, you ask, do heat pumps have a recomended "flow rate range"? Well this is because in a practical system, moving the secondary fluid ie the pool water is not free, ie it takes energy to move, and as the dynamic loses in a flowing system go up with the square of the velocity, trying to ram too much water through the heat exchanger becomes counter productive. In a practical heat pump, the size of the heat exchanger is set by limits, a larger exchanger costs more, takes up more space, is harder to seal and harder to make work evenly.

8:06 That's not a real shark.

Not happy with your electricity work Dave! Unprotected corro that powers it fails as3000 standards.

9:28 1/6 of the flow heated up by 3 degrees is exactly the fucking same as heating the whole flow by half a degree! x - initial water temperature 5x/6 (the water bypassing the heat pump) + 1/6(x + 3) (the water being heated up) = 5x/6 + x/6 + 0,5 = x + 0,5 It doesn't matter, the water is heated up the same. You spend so much time reiterating the same over and over and don't ACTUALLY explain why the heat pump is so capricious and wants such a low flow rate.