Storms, the garden, the heat pump - bit of a catch up

Sunday morning was gloriously sunny so a couple of hours in the garden was fun. With work during the week and a wet n windy day on Saturday I've barely looked at the garden.
Behold - the ravaged spring greens aka caterpillar central. I've tried picking off the caterpillars and feeding them to the hens but in all honesty I don't think the hens like them; the hens easily demolish slugs and worms but perhaps these hairy black and yellow (cabbage whites) caterpillars aren't awfully tasty.

The ravages of Autumn....we've had some proper wild seasonal weather now; this is Loch Lomond on Saturday, looking more like the sea than an inland water. The changing stormy skyline looks impressive and its great having a refreshing walk by the Loch; but also nice to get home to a roaring woodburning stove and the cosiness of the house. Last night the heat pump switched itself to winter mode which essentially means its been consistently cooler outside now (ie the average outdoor temp including nighttime is below 10degC) so if the internal temp drops then the heating will come on in the house. For us we've set the internal temp to 20deg, although its usually 2 or 3 deg cooler upstairs where we have no heating.
Not sure if I'm pushing my luck by trying to sow a few seeds this late but 2 weeks ago I carved out three mini-plots with some old Aberfoyle slate and distributed spinach, sorrel and mispoona. The latter is a combination of mizuna and tatsoi; essentially an oriental style green which should work well as a salad or cooking vegetable. I tasted a few leaves today, it has a full buzzy vibrant taste like peppery rocket. So long as we get a bit more sunshine I think we'll get some pickings through October. Nothing ventured....

Other parts of the veggie garden are still in great vigour; we've just finished the courgettes and cauliflower but have recently started harvesting savoy cabbage. Brussel sprouts are forming nicely, the leeks are growing and of course the ever exuberant chard. Plenty of iron rich greens!

There's still plenty of colour in the robust calendula which seem to have survived the early Autumn storms. I do like this flower, its so simple, so happy. When I remember I pick a few heads and pluck then dry the petals; they make a good addition to a bath for relieving excema and dry skin. Even better when placed in a muslin type bag with organic porridge under a running tap - it really works.

Heat pump installation

Work started on installing our heat pump last week. We have specified a Nibe 1240-5kW - the smallest capacity they make - with integral 'tank-in-tank' hot water cylinder. It 's a very neat unit, being the same size as a 1.9m tall fridge freezer. The pipework next to it will be ultimately enclosed in a cupboard which will still have some storage space at the front, whilst allowing access to the pipes at the back if need be.
Specifying a heat pump uses the opposite logic to specifiying a combustion boiler, as it must be just undersized to operate at its most efficient when taking into account the building's heat loss and anticipated peak heat requirement. The reason for this is that heat pumps dislike being 'cycled' - switched on and off - and actually benefit from running for longer periods at a time than conventional boilers. In extreme circumstances where, say, there is significant heat and hot water demand (eg. Christmas with visitors!) then the heat pump employs an electrical element to supplement itself, but the trick is to set things up so this hardly needs to be used at all, electricity being a relatively high-carbon form of energy.
The unit is being installed in our utility room where all the pipes from the ground loop, hot and cold water, underfloor heating and 1st floor radiators/towel radiators terminate. The guys are making a neat job of connecting this spaghetti together and hopefully by late next week we should be in good shape to switch on and get some heat into the 40 tonnes or so of concrete which forms the floor slab.
As it happens one of the founders of the heat pump supply company - Ecoliving - popped round yesterday to look at our windows (he's building an extension to his own house!) and he told me that the heat pump even had a setting to dry the floor slab out over a four day cycle, this will be important before we fit engineered board flooring.
Anderson Floor Warming of Glasgow are doing all of the plumbing in the house using a German plastic/aluminium pipe system. Hot and cold feeds are fed to manifolds from which each tap is fed, thus reducing pipe runs. Also the hot water feed is circulated from and back to the hot water tank at peak use periods (controlled by a timer) such that when a hot tap is switched on, hot water appears almost instantly.
Apart from the plumbers, the rest of the guys on site have never built a house with a heat pump in it and we are all waiting in anticipation for switch on!

Heat Pump: Part 1 - ground loop

As previously mentioned we have opted to use a ground source heat pump to provide both space and hot water heating. With no mains gas, an adjacent field and the opportunity to design a well insulated house from scratch with underfloor heating, the heat pump was the lowest carbon and lowest running cost option for East Cambusmoon.
For anyone considering a heat pump for their own house there aren't that many situations where it is the most cost effective and efficient choice, and certainly if you have the luxury of a mains gas supply a high efficiency gas boiler, coupled with say solar thermal panels will likely be a lower capital cost and running cost option than a heat pump doing both. If not on mains gas, then the costs need to be compared to LPG or oil and the decision will largely depend on the type of heating distribution system you already have, ie. radiators or underfloor heating. For the same heat input to a room, radiators need to be run at a higher temperature than underfloor heating simply because the heat emitter is concentrated into a relatively small wall hung panel, rather than the entire surface area of the floor. The problem with heat pumps is that their efficiency rapidly decreases in proportion to the heating medium temperature, such that running small radiaors from a heat pump is a bad idea. This can be alleviated to a certain extend by increasing the size of radiators so they can be run at a lower temperature.
Then there's the heat collection system, in our case this being a 300m length of 40mm diameter pipe buried 1.4m underground. This particular aspect of our build was a separate 'client item' from the main build contract so Debs, me, Stewart the digger driver and £60k's worth of band new JCB set to for four days of hard graft to get this pipe buried in the ground to in such a way as to absolutely maximise every joule of energy that could be sucked out of it .....which of course would be continuously be replenished by the sun. In effect, a huge solar panel!
In designing the collector system, we followed the heat pump manufacturer's (http://www.nibe.com/) advice on pipe depth, separaton and layout. Our supplier (http://www.ecoliving.info/) also offered advice on site and once certain of our plan, we got cracking! We ended up digging three 40m trenches, each 2m wide and 1.5m deep at 4m centres. We also imported 35 tonnes of sand to cover the pipe below and above to avoid the possiblity of damage from sharp rocks when backfilling and to ensure good contact with the ground. Bfore covering and backfilling, the pipe was pressure tsted and to finish off, fed into the house via the 'slow bend' duct pipes already built in to the floor slab.