Incompetent Installers , incompetent regulation Do I need a MIM-B19N?

Getting Started
81

Hi Trystan,Christian,William, Glyn

A Question?

Should my Flow water Temperature ALWAYS be controlled by the Weather compensation Graph ?
** OR **
Should my Flow Water Temperature be controlled by the Weather compensation ONLY when the room Temperature is below the Room Thermostat demand Temperature.

With the first option I am presented with numerous Electricity consumption warnings during cold weather!

With the second option the Heat Pump remains OFF for long periods during the night.
Is this advisable?

To Samsung Heat Pump users

The First option is set by the default setting of Field Option 2093 selected with 2091 and 2092 NOT used.

The Second option is set when Field option 2091 is used with options 2,3 or 4.

Can anyone confirm that
Field options 2 , 3 and 4 select different values for the Weather compensation Thermostat Hysteresis .

Hysteresis being the difference between the Thermostat switching ON when the Flow Water Temperature is rising and switching OFF when the Flow Water Temperature is falling.

ian

82

Hi Michael,

My opinion is that energy generated = heat output.

But, the Samsung Heat Pump manuals , published in 2013, appear , as always, to explain nothing!

The Manuals, presumably written at great expense appear to have been translations from the original Korean into a multitude of other languages. The Translators themselves having no experience with the installation and maintenance of the physical Heat Pump.

I could recite innumerable complaints about the absence of proper , up to date manuals , but, do appreciate Samsung’s problems.

No up to date, Technical Authored , corrected manuals, are available.
I don’t blame Samsung…

Writing for “Sun” Readers is different from writing for "Guardian " Readers but writing for le Figaro Readers must be very different from writing for Die Welt readers !.

ian

83

Hi Trystan,William,Christian and Glynn,

Is COP the only way to compare a Heat Pump with a Gas Boiler?

I have again been pondering the differences between my new Heat Pump and my old Gas Boiler.

The COP of the Heat Pump is Efficient .
But
The Gas boiler has a power advantage of 25Kw/%Kw = 5 to 1.

The Gas Boiler can heat my living room, at leas,t five times faster than my Heat Pump.

The Thermal conductivity of my Living room is 78 Watts per degree C.
When the outside Temperature is -5 and I require a room temperature of 21 C , my living room would leak 78 x ( 21- (-5) ) = 78 X 26 = 2.028 Kw .

The Heat Pump would require a power greater than 2 kW to increase the room Temperature at an outside Temperature where the Heat Pump output power is little more than 2 kW.

The Flow water Temperature demand would be 45 to 50 C from temperature compensation , expensive!

In practice my heat pump cannot reach the set temperature until 1800 , with the Heat Pump complaining of excessive energy demand!

My old Gas boiler could, however, easily reach the required temperature in 30 mins during the beast from the east.

OK , the Gas boiler is much more inefficient , but I can avoid hypothermia!

Is COP the only criteria ?

ian

84

@iantelescope - to maximise efficiency I think you want the flow temperatures as low as possible, so seems you should always use weather compensation.

With the second option the Heat Pump remains OFF for long periods during the night. Is this advisable?

Assuming the objective is to minimise cost. This likely depends on the heat loss of your house and temperatures expected in the morning as well as the cost of electricity in the morning vs overnight, and maybe other variables.

I am trying to get my weather compensation values so that the heat pump always on achieves a steady state for [supposedly] maximum efficiency.

My [likely flawed] logic is explained in non heat pump terms as follows.
Drive 50mph for 6 hours go 300 miles OR drive 3 x 1 hour slots at 100mph (on the de restricted part of the autobahn of course) with two 90 min breaks and go [the same] 300 miles. One journey will be £20 cheaper than the other.

I think this could be demonstrated with [edit - delta T * flow] replacing speed and kWh heat replacing miles traveled, need to find or construct a model to check this.

85

Hi William ,

You make one of my points admirably.

How to design a "Smart algorithm " to optimise energy loss against Hypothermia.

My other point is "will the Heat Pump be damaged by being switched OFF during the night?
For my Samsung what options do i choose from the Field parameters 2091 … 2093 options 2,3 or 4.

ian

86

It’s a good question and you’ve hit upon one of several factors that could certainly sway in favour of the gas boiler especially during times of extreme cold and high electricity prices. Especially if you are reducing your living area as well as you have mentioned.

A heat pump system is usually designed to meet the heat load of the whole house at the design temperature e.g -3C. The radiator system should be designed to be able to output this heat demand at a flow temperature that is in the 40-45c range (if the heat pump is to remain reasonably efficient at this temperature). If you reduce the number of rooms being heated, the rooms that are still being heated will require more output from their radiators in order to compensate for the higher amount of heat loss to the unheated rooms next door. This pushes up the flow temperature required from the heat pump and reduces the COP. In some cases this can even result in no electricity saving as the lowering COP cancels out the saving of reducing the number of heated rooms (Heat geek gives an interesting example here: https://www.youtube.com/watch?v=zpTVIeUh04E - note that the heated rooms in his example do not share the same walls, the results change if the heated rooms share walls with each other)

In my case I can get an energy saving through zoning, but it is still at the expense of COP. The following are theoretical heat loss calculation results using https://openenergymonitor.org/heatlossjs rather than actual monitored experience but are interesting nonetheless:

  1. Example 1: All rooms heated, internal doors open, -3C outside, 19C in the livingroom, mostly around 19C in the rest of the house. Heat demand is ~4.2kW, Flow temperature: 40.3C, COP should be ~2.9, electricity consumption 1.45kW.

  2. Example 2: Only the livingroom and kitchen heated, all other radiators turned off, 19C in livingroom (-3C outside). Heat demand: 2.6kW, Flow temperature 45.8C, COP should be ~2.5, electricity consumption 1.0 kW (this would leave the rest of the house unbearably cold).

So it may well be that by reducing your living area and needing to compensate by running the radiator temperature in the remaining rooms higher the COP will drop below the gas boiler parity point. This said if the performance is sufficiently better in warmer periods the average COP or SCOP should still be competitive with gas over the year.

87

Hi Trystan,

Again, many many thanks for expanding my understanding!

Heat Loss

Given COP = Energy Generated / Energy Consumed.

The emphasis on COP tends to obscure the Energy Consumed or lost.

At every instant ,the Energy Consumed by the house is shown on my Samsung Display as currently

Energy Consumed = 800 Watts

The Outside Temperature is currently 4.7 C.

My Living Room Temperature is currently 19.4 C.

The Thermal conductivity of the house is

House Thermal Conductivity = 800 / ( 19.4 - 4 .7) = 54 Watts per degree C.
( Note, Previous experimental Measurements gave a value of 78 W/C for my living room alone!)

With the Thermal Conductivity could a better Thermal model of my house be produced?

Has anyone else measured their house Thermal Conductivity?

ian

88

Hi Trystan, Christian, William

A moderate frost has returned to my area, with the results shown for the 16th to 17th January shown in the following graphs

Energy
The Energy , Watt hours consumed by my Heat Pump is shown in
energy

The Total energy consumed between 10 am 0n the 16 to 10am on the 17th was 18KW.
At this rate my monthly consumption would be 540Kwh .

Power
The Power , KW , consumed by my Heat Pump is shown in
power

The oscillations shown between 5 am and 8 am are caused by the Water Law Thermostat switching ON when rising above the upper Set Temperature and then falling to the Lower Water Law Thermostat Temperature.

Water Flow Temperature
The Absolute value of the Water in the primary water loop is given by
abs_temp_HP

The Oscillations in the Water flow temperature are again very evident.

Radiator Water Temperature
The Absolute value of the Water in the Radiator water loop is given by
abs_temp_Rad

The Radiator water Temperature is circa 2 C below the Heat Pump Water Temperature. Allowing that the flow rates between the Heat Pump and Radiator loops should be similar , the Heat Exchanger is loosing circa 5% of the heat energy.

Conclusions

1 The Oscillations in the power and Water Temperature are caused by the Flow water taking the path of least resistance, bypassing the Volumiser tank.

2 The Monthly consumption , at 540 Kwh is unaffordable, representing Fuel poverty.

3. The Heat pump cannot maintain a required temperature of 21 C in any room at any time of the day when the outside temperature is less than +3 C.Hypothermia.

What can I do ?

ian

89

I wouldn’t say that 540kWh is excessive, it works out at 17kWh a day, equivalent to about 61kWh of heat if your CoP was good at 3.5 and assuming that this is just the energy consumed by the heat pump.

Our house has averaged 115kWh per day for heating over the last month

Whether the consumption is excessive or not depends on many factors which aren’t apparent.

90

Yes it seems strange that that volumiser is in parallel with the heat exchanger, it would make more sense to me for it to be in series, is it just two pipes to the volumiser or are there 4 pipes by any chance? Your diagram showed two pipes… @johncantor does that make any sense to you?

A well designed heat pump should be able to meet it’s design criteria assuming it has been designed well.

What were the internal temperatures in your house yesterday? and the external temperature?

91

Can you point me to the diagram? series does sound very strange

92

Here’s the diagram @johncantor, thanks!

93

did you mean parallel?

94

Sorry, i did mean parallel would be strange, but diagram is even stranger.
when heating, flow is split (by unknown proportions) through volumiser and heat exch, yes parallel. In DHW mode, i guess nearly all bypasses both.
Prob with complexity is its so prone to going wrong

95

Hi Trystan and John,

“A well designed heat pump should be able to meet it’s design criteria assuming it has been designed well.” Trystan.

My Heat Pump was never designed.

I asked for a Samsung because the Samsung “did not require either a Buffer tank or Heat Exchanger”.

I received a Samsung equipped with a heat exchanger.

Two months after the “installation” the Heat Pump began Cycling ON and OFF with a 8 minute period.

Both Samsung and Telford, the Tank Maker, advised that a Buffer /Volumiser be fitted to stop the cycling.

Buffer-sizing-11
Buffer-sizing-111499×1749 287 KB

Samsung agreed to repair the Heat Pump and fit the volumiser tank.

My "installer " described Samsung’s prices as “ludicrous”.

The “installer” fitted the tank without help from either Samsung or Telford.

The Position of the Volumiser tank was taken from Kensa
Buffer-tank-schematicR

Because the Energy stored in the Volumiser tank when connected across the Heat Pump would be
Energy Stored in Volumiser = Maximum Water Flow Temp X Spec Heat of water X Volumiser Volume
Energy stored ( loss) = 50 X 4.3 X 50 = 10.75 KWh

If the Volumiser tank were connected across the Heat Exchanger however
Energy Stored in Volumiser = Average Water Flow Temp X Spec Heat of water X Volumiser Volume
Energy stored ( loss ) = 35 X 4.3 X 50 = 7.525 KWh.

Since the loss , 7.525 < 10.75, the Volumiser tank was fitted across the Heat Exchanger.
Samsung-inchinnan.pdf (20.1 KB)

The Heat Pump now has two Cycling periods
1 The Cycle period set by the Volumiser Tank when supplying the Heat Exchanger and Radiators.
OR
2 The Cycle period set by the Volume of the HOT Water Tank heating coil.

The Difference accounts for the two Cycling periods shown in the HP Absolute Temperature graph .
abs_temp_HP

Many thanks for your help.

ian

96

Hi John and Trystan,

Sorry about my Diagram.

The size was chosen by Samsung confirming the values given in

Buffer-sizing-11
Buffer-sizing-111499×1749 287 KB

The position of the Volumising tank corresponds to that shown by Kensa
Buffer-tank-schematicR

My “installers” are not designers , only plumbers.

ian

97

Hi Billl,

"I wouldn’t say that 540kWh is excessive, it works out at 17kWh a day, equivalent to about 61kWh "

Many thanks, Bill , for giving me a comparison figure for my consumption .

Friday 13th …
My COP varies wildly from a low of 2.6 on Friday 13th January ( it had to be Friday 13th ! )
to a high of 4.13 on the 5th of January.

The very Low COP parameters correspond to those with low , or very low, outside temperatures.
energy

The Low temperatures experienced last night , 16th to 17th January , consumed 12 Kwh between 1200 and Midnight , with another 3 Kwh consumed during the period of Oscillation during the night.
The COP was very low at 2.77.

My COP is, as expected, seen to fall with lower outside Temperatures.

With a low COP my Heat Pump is also consuming more energy in Cycling ( ~3 Kwh ) and de-icing ( 2 Kwh).

My current living room temperature is 18.2 C pumping continuously from 14 C at 8 am this morning!

ian

98

The Kensa example is OK… if rads stop/reduce, it can flow around the buffer. not sure it helps ‘volumise’ for defrost if the flow rate in the HP happens to be the same as radiators. Anyhow, the diagram I saw with ‘volumiser’ in parallel had heat exchanger, so not connected to the variable-flow radiator flow side of things.

99

Yes the kensa example seems to specifically refer to the use of the buffer as a bypass for “when zone valves close flow is directed through the buffer vessel” which makes sense from a safety perspective if you don’t have control over the zones. But as you say @johncantor when in parallel with a heat exchanger which is always open it doesn’t sounds like it will do anything apart from perhaps provide another route for the water to mix - reducing efficiency??

100

any chance of a close-up picture of the heat exchanger @iantelescope, should be some specification printed on it somewhere as well?