Gas usage down, approx. 200kwh through Spring and Summer.
House generally drier and fresher.
The Solarventi unit, as discussed in this blog elsewhere, is not going to save money over it's lifetime, but it is very pleasent on a spring or autumn sunny day.
In the winter, Dec/Jan the sun is not powerful enough for the unit to raise the temperature of the air, so dry cool air enters the house. My advice - turn the unit speed right down to minimum at that time of year.
Having said that, this year has been poor for crisp sunny days.
Now it's February, and finally the unit is able to perform at full speed again.
As for the Mitsubishi Heavy Industries air-to-air hyper-inverter that we installed in September 2009, that has seen our electric usage double over the winter months, but gas half. Again, with low temperatures over Dec/Jan, this is to be expected, but this will prove it's worth once temps reach 7 degrees C or more. At that point gas usage will be minimal.
God bless you.
Wednesday 24 February 2010
Thursday 17 September 2009
From solar panels to Air source heat pumps
The solarventi is enjoying a rest. What a grey week it has been. Nevermind.
We have the answer to warm but dull days.
And it is an air-to-air heat pump, also know as an inverter, also known as an aircon unit.
We are pleased to announce that the Solarventi on the south side of the house has been balanced by an aircon unit on the northside.
The aircon unit uses refrigerant and a pump to extract heat and pass the heat energy via the refrigerant either into or out of the house.
Hence it is known as an inverter. It will heat or cool the house as your need changes. This model, mitsubishi heavy industry SRK20ZIX-S is the second most efficient on the market at the moment. (The hitachi model slightly more efficient is almost twice the price, so no economy there, bit of a posing stainless steel job I understand). This model has a COP of 5.5. i.e. generates 5.5Kw heat for every 1 Kw of electric used.
Installed by http://www.orionairsales.co.uk from bedfordshire.
Helpful bunch, 15% VAT on the web site is 5% if they install for you, as per current Govt VAT concession.
I recommend them. But please make sure they arrive with the exact model you ordered. It seems nobody including me noticed the switch to a far less efficient model by their supplier. Nearly collapsed with shock when I double checked.
As it is, 3 days in, and the unit is warming more rooms than I could have imagined possible, with outside temps of between 10 and 18 degrees c it's perfect. And puts off the day of the gas central heating starting up. Fantastic.
So air source heat pump downstairs, solarventi upstairs. This is good news for our fuel bills this autumn. I look forward to seeing how it works out in the coldest winter days, when the heat pump is less efficient.
We have the answer to warm but dull days.
And it is an air-to-air heat pump, also know as an inverter, also known as an aircon unit.
We are pleased to announce that the Solarventi on the south side of the house has been balanced by an aircon unit on the northside.
The aircon unit uses refrigerant and a pump to extract heat and pass the heat energy via the refrigerant either into or out of the house.
Hence it is known as an inverter. It will heat or cool the house as your need changes. This model, mitsubishi heavy industry SRK20ZIX-S is the second most efficient on the market at the moment. (The hitachi model slightly more efficient is almost twice the price, so no economy there, bit of a posing stainless steel job I understand). This model has a COP of 5.5. i.e. generates 5.5Kw heat for every 1 Kw of electric used.
Installed by http://www.orionairsales.co.uk from bedfordshire.
Helpful bunch, 15% VAT on the web site is 5% if they install for you, as per current Govt VAT concession.
I recommend them. But please make sure they arrive with the exact model you ordered. It seems nobody including me noticed the switch to a far less efficient model by their supplier. Nearly collapsed with shock when I double checked.
As it is, 3 days in, and the unit is warming more rooms than I could have imagined possible, with outside temps of between 10 and 18 degrees c it's perfect. And puts off the day of the gas central heating starting up. Fantastic.
So air source heat pump downstairs, solarventi upstairs. This is good news for our fuel bills this autumn. I look forward to seeing how it works out in the coldest winter days, when the heat pump is less efficient.
Saturday 22 August 2009
Solar panel salespeople
Solarventi sales process was so straight forward. The gentlemen were able to confirm over the phone from photos and internet bird's eye photos of our house.
No site visit was necessary before arrival for installation. Saves precious resources. Saves me time.
Compare this with SolarEssence from Thetford.
They cold call and on agreement send round a "marketing executive" salesperson who want to visit and take 2 hours of your time without adding to your day.
Retails at 12,000 he says, when I dismissed his price of over 6,000 out of hand.
The amount of solar radiation in Dec. is less that 1 KWh per m2 per day on average in the UK. Therefore the idea that you can "heat your house" or provide more than 70% of your hot water requirements annually without some large m2 of vacuum solar tubes and some very efficient heat storage is just fantasy.
Even if gas rose to 10 times it current price their offering would not have saved me over 6,000 in it's lifetime. And there are much more economic, efficient, ways of being "green".
e.g. Biogas, or wood fuels, or electric efficient heat pumps.
The solarventi is an exception in my view. It does more than just add hot air. It has freshened our bathroom upstairs less over the summer months with the sun so high. But it has been more active as August has passed and the sun's angle of incidence on the panel has increased. Remember the panel is close to vertical.
The dehumidifying action increases too.
I was able to switch off the central heating earlier this year than previous years and I anticipate the central heating will come on later this autumn. I am conscious that the solarventi is part of the reason for this. It's 17 degrees outside this morning but bright sunshine. The central heating might have kicked-in over night (but it's not switched on). But the solarventi was purring away with the early morning sun.
We visited a friend last week, it's mid-August, who had windows on trickle vent/closed upstairs and the mugginess in the bathroom was a reminder where we would have been without the solarventi.
No site visit was necessary before arrival for installation. Saves precious resources. Saves me time.
Compare this with SolarEssence from Thetford.
They cold call and on agreement send round a "marketing executive" salesperson who want to visit and take 2 hours of your time without adding to your day.
Retails at 12,000 he says, when I dismissed his price of over 6,000 out of hand.
The amount of solar radiation in Dec. is less that 1 KWh per m2 per day on average in the UK. Therefore the idea that you can "heat your house" or provide more than 70% of your hot water requirements annually without some large m2 of vacuum solar tubes and some very efficient heat storage is just fantasy.
Even if gas rose to 10 times it current price their offering would not have saved me over 6,000 in it's lifetime. And there are much more economic, efficient, ways of being "green".
e.g. Biogas, or wood fuels, or electric efficient heat pumps.
The solarventi is an exception in my view. It does more than just add hot air. It has freshened our bathroom upstairs less over the summer months with the sun so high. But it has been more active as August has passed and the sun's angle of incidence on the panel has increased. Remember the panel is close to vertical.
The dehumidifying action increases too.
I was able to switch off the central heating earlier this year than previous years and I anticipate the central heating will come on later this autumn. I am conscious that the solarventi is part of the reason for this. It's 17 degrees outside this morning but bright sunshine. The central heating might have kicked-in over night (but it's not switched on). But the solarventi was purring away with the early morning sun.
We visited a friend last week, it's mid-August, who had windows on trickle vent/closed upstairs and the mugginess in the bathroom was a reminder where we would have been without the solarventi.
Monday 1 June 2009
Long hot days
Monday 1st June; we have had a lovely weekend of continuous sunshine here in Peterborough.
I think we have a better understanding of the Solarventi solar unit in this weather.
On the control unit I have kept the max. temp. setting needle at a 2 o'clock position, probably 25 degrees. The needle goes from a temp.setting of 15 degrees at 8 o'clock, clockwise on the dial to a setting of 30 degrees at 4 o'clock on the right of the dial.
The outside temp. thermometer reading reached 25. The solarventi unit stopped running early afternoon. It recommenced at some stage late afternoon I think, I assume once the unit had cooled down. The relative humidity measured 21% on the bathroom hygrometer whilst the unit was running. When it stops, the humidity climbs very quickly back to 40+.
We also leave the bathroom window locked-open. We find this balances the extreme drying capability of the solarventi unit with our need for humidity. You can have too much of a good thing.
In future posts I will continue to give results from our solarventi unit, but in addition I will explore the use of solar power in the form of heat pump / inverter units. These units transfer heat from air outside the house to warm the inside of the house. It will be interesting to see how these investments compare.
I think we have a better understanding of the Solarventi solar unit in this weather.
On the control unit I have kept the max. temp. setting needle at a 2 o'clock position, probably 25 degrees. The needle goes from a temp.setting of 15 degrees at 8 o'clock, clockwise on the dial to a setting of 30 degrees at 4 o'clock on the right of the dial.
The outside temp. thermometer reading reached 25. The solarventi unit stopped running early afternoon. It recommenced at some stage late afternoon I think, I assume once the unit had cooled down. The relative humidity measured 21% on the bathroom hygrometer whilst the unit was running. When it stops, the humidity climbs very quickly back to 40+.
We also leave the bathroom window locked-open. We find this balances the extreme drying capability of the solarventi unit with our need for humidity. You can have too much of a good thing.
In future posts I will continue to give results from our solarventi unit, but in addition I will explore the use of solar power in the form of heat pump / inverter units. These units transfer heat from air outside the house to warm the inside of the house. It will be interesting to see how these investments compare.
Monday 18 May 2009
Dry throat
O.K. so I should have seen this coming.
The solarventi SV14 unit, in full sun all day, has so reduced the humidity from the house norm of about 60%, to below 20%, (According to our hygrometer display relative humidity is "LO%" which I think means it can't measure below 20%) that it has dried my face and throat.
How silly of me, to sit in the study, down the landing from the bathroom where the solar panel pours in the very, very, dry air. Not only are the towels over the banister like starched sheets, but I need to have a long cool drink every 5 minutes.
The air is so much drier than the outside air, I don't think I was really anticipating the amazing dehydrating qualities of this unit.
I was quite uncomfortable, so I threw the windows wide open; this is May in Peterborough, and outside temps have not reached 20 degrees C yet. Great stuff. But there is a problem. You can't tell what the weather will be exactly, and you can't leave the windows open just in case. And you can't afford to dry the house to a crisp. Literally, arrive home, 2 minutes upstairs and my throat is dry.
The longer term solution, when I am going out for the day and can't leave the windows wide open, is to work-out the best temperature setting on the solarventi controller. It's not too difficult to gauge what temp you have set. The panel's selector needle shows 15 degrees as the lowest value (anti-clockwise) and 30 as the highest. However, when 30 degree air was being pumped into the bathroom, the fan did not hesitate for a moment, it continued at full speed. Perhaps 30 doesn't mean 30?
I don't have the answer to this yet, so I chose something around where I imagine 25 would be, setting the needle at a position of TWO O'CLOCK on the temperature gauge.
I need to ask Solaventi UK for their opinion on the temp.setting best suited.
The other option is to override the fan speed. (This is the other needle on the controller for the solarventi unit) I have concluded that since the dehumidifying aspect of the panel seems to correlate with temp. (higher the temp. the lower the humidity) then setting temp. cut-off at 25 should limit the humidity to a sensible range and suit all weather patterns.
Like today, occasional sunshine, the panel rarely reaches 25, but it is worth having the fan on full power whilst it approaches that temp.
Yesterday, Sunday, when the sun was shining, I was able to check my settings, since the hygrometer showed 24 degrees and 31% relative humidity. This seemed reasonably comfortable to me.
I imagine if customers have installed these larger solarventi units without the controller in their homes, it will prove necessary to switch the unit off in summer. Or lock the windows in an open position. Personally I did not find this enabled enough flow of air into the house.
The driver for me, my aim on installation of the solarventi model, has always been to dry the bathroom and reduce/remove the pin mould problem. No sign of the mould at the moment !!! I am very optimistic on that front.
If my main aim had been to heat the house (upstairs at least) to a very comfortable 28+ degrees then I would now consider it an un-realistic goal, since the dehumidifying behaviour of the unit is too powerful to allow the unit to keep running at that high a temperature with the windows closed, in my opinion.
Wednesday 29 April 2009
April sunshine
Forget the showers, this last week or so has been sunshine 9 days in succession. How often is April like this? In fact it's another bright day today.
When the sun is shining the solarventi panel has reduced the bathroom humidity; 7am bath is run, humidity climbs to near 100%; with the panel operating in full sun, by 8:30 am the bathroom is registering humidity down to 45%, (bathroom norm by midday on an overcast day is still 65%) .
When I return at 5:30pm (before evening baths) the hygrometer is still measuring the bathroom at 50% humidity, and upstairs along from the bathroom the temp. has still been 23-24 degrees C. This is long after the sun has moved round the house away from the panel.
Downstairs away from the benefit of the hot air from the panel it has been cooler i.e. at the house norm of 20.
I find it very pleasant upstairs. The house is not normally as warm as 24 at 5:30pm even on a warm summer's day. The house doesn't have large south facing windows.
All this and temperatures outside the house have been moderate, between 10 and a max. of 18 degrees C.
So I am pleased with performance these last few weeks.
When the sun is shining the solarventi panel has reduced the bathroom humidity; 7am bath is run, humidity climbs to near 100%; with the panel operating in full sun, by 8:30 am the bathroom is registering humidity down to 45%, (bathroom norm by midday on an overcast day is still 65%) .
When I return at 5:30pm (before evening baths) the hygrometer is still measuring the bathroom at 50% humidity, and upstairs along from the bathroom the temp. has still been 23-24 degrees C. This is long after the sun has moved round the house away from the panel.
Downstairs away from the benefit of the hot air from the panel it has been cooler i.e. at the house norm of 20.
I find it very pleasant upstairs. The house is not normally as warm as 24 at 5:30pm even on a warm summer's day. The house doesn't have large south facing windows.
All this and temperatures outside the house have been moderate, between 10 and a max. of 18 degrees C.
So I am pleased with performance these last few weeks.
Wednesday 1 April 2009
Hygrometer
On Saturday we had scattered showers, no make that storm clouds, (occasional heavy hail) with the odd patch of blue sky. The hygrometer in the bathroom confirmed the solarventi panel had been in action. When I returned from my travels over lunch, the relative humidity still registered 40%, and temp was 21.7 degrees C. even though the sun was not out that much.
The house "norm" is 55-60% and our central heating is set at 20 degrees.
(Fig 1. Bathroom ceiling, with input vent from Solarventi panel.)
OK, so my hygrometer has fallen from it's mounting, as you can see to the right, it now rests on the wall cabinet (far right, behind the Johnson's baby shampoo bottle). The readings are none the less encouraging. Sunday was dry and bright. The images were taken that afternoon.
As I stood peering at the hygrometer, my breath caused the humidity reading to rise from 23 to 27 in seconds. Humans are a major cause of damp in houses too. Just breathing adds moisture to the atmosphere.
The two temperature readings are internal 27.9, and external 18.4. The wire runs outside to a sensor on the wall behind the solarventi panel. The general outside temp was 10 degrees at the time, or so the car instrumentation said as we drove home from church. So the external temp is boosted by being in proximity to the panel.
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