DIY air-to-water heat pump

Why a heat pump instead of gas: preparation, assembly

If necessary, an alternative to blue fuel can be not only a solid fuel boiler with a heat accumulator, but also a heat pump. Want to save on gasification? FORUMHOUSE offers a story from a user with a nickname batt87, which heats the house with a homemade heat pump instead of piping gas.

Why, despite the gasification of SNT, it is impossible to connect

I have been living in SNT in a suburb of Krasnodar for the third year, there is no gas, electricity at the usual rate of 5.38 rubles. day and 2.89 rubles. night. First, I'll tell you about gas.

We at SNT already have a project for the gasification of our and neighboring SNT and those. conditions for connection to an existing hydraulic fracturing (gas distribution substation) 2 km from us. The project cost to date is 1 mln. rub., we did it 5 years ago, together with neighboring SNT, in the end it came out 3000 rubles. per person, i.e. out of 2,000 plots that appear in the project, 300 people donated money for the project.

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Now the gas workers have roughly calculated how much the installation of the pipeline and the installation of hydraulic fracturing will cost us at SNT, as a result, about 8 million rubles came out. rubles, if you create a group of the same 300 people, and in our country, let me remind you, in the project for gasification of 2000 sites, it will turn out from each 8 million / 300 people = 27 tons, round up to 30 tons. After installing the hydraulic fracturing, we will need to "throw" pipes through the streets and bring taps to each section, this is the second part of gasification, there will likely be an increase in those wishing to participate, and for every 1 km. streets I think we will find 50 people who want to bring the GAS valve to their site. In terms of money, it will be slightly cheaper: 6 million. per 2 km., it turns out 6 million / 100 people = 60 tons. Already 60 + 30 = 90 tons, round up to 100 tons. In principle, a great price to bring gas to your site.

But the last part of GAZification with a pipe plant into the house, which is about 30 meters of pipe, kills all initiatives. T. k. 100 t. p. GORGAZ simply takes it as a bribe under the guise of any unnecessary nonsense, without which the GAS valve in your house will not be opened. For example, they require the installation of a meter for 10 tons, instead of 2.5 tons, project approval costs 10 tons, although it should be 0 rubles. It is suggested that work on the installation of 30 meters of pipe should be performed by "proven" guys whose prices for material and work are at least 2 times higher. When work + material should cost 50-60 tons, you are considered 100-120 tons.

When everything is ready and paid for, 3 different people come from GORGAZ to enter your piece of pipe (30 meters) into operation (check the pipe, check the boiler, check the taps, check the project, etc.), and it still costs 30 tons. Although the installation was done by their "proven" guys and all acts and tests are required when the contractor hand over his work, as a result, an overpayment of 10 + 60 + 30 = 100 tons.

100 (pipe) +80 (to the house) +100 (bribes) = 280 tons of rubles have already come running, this is a lot, and it is unlikely that with such numbers we will recruit from 2000 people and 200 people. Therefore, I realized that we will not see GAZ for 5-10 years.

House parameters

House 7x12 m., Two-story, from rubble bricks, wall cake: half a brick / air 3-4 cm. / One and a half bricks / plaster + paint. The floors are tiles.

Heating with underfloor heating, without batteries, for each floor there are 8 underfloor heating circuits. The floors, remember, tiles, under the warm floor, extruded polystyrene foam.

Heating with electric boiler EVAN 9 kW 220 V and split: two systems on the ground floor, LESSAR for 9K BTU and 12K BTU not an inverter.

I keep statistics in EXCEL on the costs of house maintenance, I like to count, check and control everything.

Concept development, components, drawings

I have long wanted to try to assemble a freon-water heat exchanger instead of the split internal block.

Why split, because splits are now so cheap that a working used external 48,000 BTU unit can be found for 10,000 rubles, this pushes for experiments.

In the summer of 2019, I started looking for a "donor" for a heat pump, I was looking for at least 24,000 BTU for a working external unit, but in summer the prices for splits are a little more expensive and there are not so many choices as in the off-season. As a result, I found a new split from Leroy, Monlan 12K BTU with a punched internal block for 8000 rubles. (a new one costs 13,000 rubles)

I decided to make the housing of the internal heat exchanger from a metal gas cylinder of 50 liters, I also bought it in Leroy for 2500 rubles, in the summer the cylinders are cheaper by 500 rubles, in the winter it costs 2999 rubles.

I found a store in Krasnodar with equipment for refrigeration equipment and bought a 3/8 ”copper pipe corresponding to my split 15 meters (2500 rubles) and 1/4 "15 meters (1500 rubles) and all kinds of corners and reductions for soldering on these pipes (they are not expensive, 20-30 rubles. each). I also bought an electrode with silver for soldering copper pipes (200 rubles) and the cheapest electrode (50 rubles) for soldering for training, I have never tried to solder copper pipes. I took the fittings for the cylinder in Leroy from ordinary steel, they are all about 50 rubles. stand.

Scheme of a heat exchanger in a 50 liter cylinder.

Implemented diagram of my heating system.

Assembling the heat pump system

• Using a fortune, I cut off the neck with a tap so that the hole was 160 mm., The cylinder itself is 28-30 cm in diameter.

• I made holes for welding squeegees 1 "4 pcs., For connection to the existing heating system (like a hydraulic arrow turned out, look in the search for what it is, why and how it works).

• Made holes for welding 1/2 ”squeegees, 3 pcs., At the bottom of the cylinder, 1 in the center at the very bottom, for slag drainage, and 2 holes for the copper pipe outlet.

• A friend welder welded on top a steel flange with an inner diameter of 160 mm and from a piece of steel 10 mm thick, cut a cover with a cutter.

• Also, a friend welded all the gons.

• Holes for bolts 8 pcs were drilled in the cover, coaxially with the holes on the flange.

• I sprinkled everything inside the cylinder with phosphoric acid and where I got it out with my hand, I cleaned it with a metal brush, after painted, primer-paint on metal from rust, all places inside the cylinder and all squeezes inside, as well painted over.

• I twisted a 3/8 ”coil from a copper tube around a normal sewer pipe 110 mm., 3/8 pipe took 10 m.

• I twisted a 1/4 ”coil from a copper tube around the same sewer pipe 110 mm., 1/4 pipe took 5 m.

• I soldered a copper reduction from 3/8 to 1/4, and soldered two copper coils, one spring from a copper tube turned out, straight under the cylinder cap (the diagram above shows how the coil is made). For the future, it is better to do the soldering later, outside the cylinder, and make the coil entirely from 3/8 ”pipe, so there will be no freon leaks inside the cylinder and it will be much easier to repair.

• I welded metal profiles purchased from Leroy to the cylinder to hang it on the wall.

Then leafing through the pages on the Internet, I came across our Krasnodar company "Teplotekhnika", which was selling an air / water heat pump at a HUGE discount for inverter compressor, with a capacity of 5 kW for heat, I booked it on the Internet and paid for it (50 tons), with little difficulty in accounting for me given away.

As a result: I have 1 factory-made heat pump and I make 1 heat pump myself. My boiler room is very small, so everything is plump, but fit.

I did the piping myself, plastic pipes are not very difficult to solder, the main thing is to measure everything accurately and more fittings before cutting the pipes. And when installing threaded connections, do not use FUM tape.

Connections with it all started flowing for me, and I redid 5 times one or the other connections on LEN + Multipak. Now all LEN + Multipak connections.