Three-phase heat pump Air-Water SAMSUNG 16kW for a house 240m2
How to provide heating, cooling and DHW (hot water) for a 4-5 member household in a 240m2 house? With one system, no maintenance, as efficient as possible and with the lowest bills.
Task: Complete the work of three other companies, on the construction of a heat pump installation for heating, cooling and hot water for a 240m² house.
Read in about 9-10 minutes! 🙂
In this project to build a heating, cooling and DHW system with an Air-Water heat pump, our task was a little more complicated and different than usual.
In general, we prefer to build the project from start to finish:
- to make the necessary heat loss calculations
- to set the necessary power of the heat pump, according to the needs of the home and climatic features of the area
- to design pipe routes and diameters
- lay power and communication cables
- to build the internal heating and cooling installation, “inflate” it with a heat transfer fluid and test it for tightness, at least 72 hours
- yes…, yes…, yes…, but NO 🙂
With this project, things were different. One had laid the pipes for underfloor heating, others had run the package of copper pipes and cables between the indoor and outdoor body of the heat pump, and the heat pump itself would be from a third company. We were the four and the last to have the honor of assembling the puzzle and, happily or unfortunately, shouldering all the responsibility.
Calculations and design of the Air-Water heat pump installation
The fact that the SAMSUNG 16kW three-phase heat pump itself had already been purchased by the customer (but not delivered and installed) did not eliminate the need for home heat loss calculations and monthly bill forecasting. In this way, we would make sure whether the power of the machine would be sufficient for the needs of the house and whether the bills would be normal for a heat pump installation.
Construction features of the house:
- two stages plus attic – total area 240m2
- external walls – masonry with standard “Quarter” bricks – λ (thermal conductivity coefficient) = 0.44W/mK
- internal walls – masonry of the same bricks – λ = 0.44 W/mK
- windows – 5-chamber PVC with triple glazing 4C/White/White – Ug (heat transfer coefficient) = 1.4 W/m2K
- floor – reinforced concrete slab with a thickness of 25 cm – λ = 1.92 W/mK
- ceiling – 20 cm thick reinforced concrete slab – λ = 1.92 W/mK
- floor height – 2.65m
- roof – four pitched – wooden structure covered with tiles with λ = 0.99 W/mK
Insulations:
- external walls – EPS 15-18 styrofoam – 10 cm thick – λ = 0.035 W/mK
- floor – fiber XPS with a thickness of 5 cm – λ = 0.033 W/mK
- roof – stone wool filling 10 cm – λ = 0.037 W/mK, between the beams of the roof structure
House heat loss calculations
In the calculation of the heat losses of each object, many factors have an influence, some mainly, others indirectly, but the more data we have, the more accurate our calculations will be:
- the building structure of each building element, for example a wall (external or internal):
- thickness and type of internal plaster
- thickness and type of masonry – bricks, reinforced concrete, aerated concrete, wood…
- thickness and nature of external plaster or adhesive for thermal insulation (for example)
- thickness and material of the insulation layer (if any)
- thickness and type of facade plaster or cladding
- and any other building materials
- windows – profile material and glazing – the structure of the glazing (double, triple…, the combination of glasses and the distance between them) is a much more important factor, from the point of view of heat loss, than the window profile itself, because it is above 95% of the building opening for windows and doors
- square footage of each element – walls, floor, ceiling, joinery, doors…
- geographical exposures of the individual elements
- calculation temperature for the region of the specific object, Bulgaria is divided into nine climatic zones
- desired temperature to maintain – every one degree more or less is a certain amount of power
- and other factors
Based on the above construction characteristics of the house with a total area of 240m2, the insulation of the individual building elements, the climatic zone in which the object is located and the desired temperature to maintain in heating mode of 23°C, the heat losses at -16°C (minus 16), reached 7.64kW.
Is the heat pump suitable for the particular house?
At first reading and glance, a SAMSUNG three-phase heat pump with a nominal power of 16kW, for a house of 240m2 with a heat loss at -16°C of 7.64kW, is quite oversized. Yes, but only at first glance.
Maybe you know, but maybe NOT, that the power of all Air-Water thermomops is given by the manufacturer only under certain conditions, and they are:
- ambient temperature +7°C (outside temperature)
- heat carrier temperature +35°C (heating installation temperature). This temperature value is suitable almost exclusively for water-based underfloor heating
- relative humidity also has an effect.
Then and only then, the Air-Water heat pump can generate 16kW of heat power, with 3.6-3.9kWh of electrical energy consumed. When changing any of the above indicators, a change also occurs in the capacity of each Air-Water heat pump.
Therefore, when designing any heating and cooling system with an Air-Water heat pump, many indicators, factors, dependencies and… Otherwise, even with the best machine/brand, we can achieve disappointing results and many high bills.
How does the coefficient of transformation (COP) of a three-phase Air-Water heat pump SAMSUNG 16kW vary?
Based on the 3-4 COP values provided by the manufacturer, at +7°C, +2°C and -7°C, additional collected data and the necessary formulas, we theoretically calculated the transformation coefficient changes of this three-phase Air-Water heat pump. This is necessary so that we can guarantee the trouble-free operation of the entire installation. Let’s confirm that the heat pump is suitable for the needs of the house in almost any winter temperature. Also forecast monthly heating and hot water bills.
How to confirm that the heat pump will guarantee the needs of the house?
As you can see from the diagram, depending on the reduction of COP – the coefficient of transformation, the nominal power of the machine also decreases. The intersection point of required to produced power is at -13°C (minus 13°C). At such outdoor temperatures, the heat pump will be able to guarantee the required heating power, ONLY from the operation of the compressor – freon cycle, at COP 1.85. At lower than -13°C outside temperatures (which are rare and relatively short-lived), one of the built-in two 3 kW electric heaters will switch on. This will ensure the necessary additional power for trouble-free heating and hot water.
How did we predict the monthly bills for heating and domestic hot water?
As usual, when calculating and designing a heat pump installation for heating, cooling and DHW, we prepare estimated monthly bills. Which naturally, after building the system, we monitor thanks to the customers and the real data of the consumed energy provided by them.
Based on the real comparisons, we have come to the conclusion that the estimated accounts are close to the real ones with a deviation of ±10%. This is relatively normal, as one of the main factors for the monthly bill is the variation of the outside temperature during the winter.
Average monthly temperature data from the nearest station to the specific site are included in the forecast calculations.
Other key factors in predicting monthly bills are:
- desired temperature to maintain
- degrees Celsius (the difference between the desired temperature and the average monthly outdoor temperature multiplied by the heating days in the month) for the site area
- supply temperature in heating mode
- DHW temperature
- volume of the hot water boiler
- specific (different for each object) power to raise the temperature by 1°C
- hours of heating per day
- transformation factor variations
- price of electricity
How did we design the heating, cooling and DHW installation with a heat pump?
After making the necessary calculations of the heat losses of the whole house and of each room separately, we set the necessary diameters and due to the main and local pipe routes.
We have calculated the number and characteristics of the required circulation pumps. The necessary power and communication cables.
The volume of the water heater, relative to the members of the household. Also the path, diameters and lengths of the water heater coil feeding pipes, power and communication cables and routes.
We have calculated the required power of the water convectors for heating and cooling, for each room, as well as the necessary cables for them.
We estimated the size and type of the collector boxes, the size of the collectors and the number of lines required.
We prepared an offer for the necessary materials, appliances and installation work.
And after a detailed discussion with the client, we moved on to building the complete heating, cooling and DHW system with an Air-Water heat pump.
First stage of the construction of the heat pump installation
As part of the pipes had already been laid (for the underfloor heating on the first floor and the bundle of pipes between the outdoor and indoor units of the heat pump), we had to make sure of their continuity. Because plasters and screeds followed, after making which, the repair would be very difficult and expensive.
So that:
- we built the supply riser lines from copper pipes
- we installed the collector boxes
- we laid the pipes for each convector in the individual rooms
- we connected all pipe routes in one closed system (organism)
- we added an expansion vessel with a pressure gauge and safety valve for 10 bar-a
- we filled and vented the installation, and left it under a pressure of 4 bar-a for 3-4 days
- we filled and inflated the bundle of copper pipes between the two heat pump bodies with nitrogen at 35 bar to make sure of their integrity.
Manifold box for underfloor heating with mixing unit, manifolds with flowmeters and thermostatic valves with electric actuators.
Collector box for three convectors on the first floor
Collector box for five convectors and one radiator.
In the meantime, we laid the necessary cables, insulations and accessories.
After we completed the first stage of the construction of the heat pump heating, cooling and DHW system, the client continued with screeds, plasters and finishing works to turn the house into a home. The entire pipework remained fully pressurized until the second stage. In order to react as painlessly and quickly as possible if someone accidentally perforates one of the pipes.
Second stage of construction of the heat pump installation
After the client completed almost all the finishing touches to the house, we stepped in to put the finishing touches on the heat pump heating, cooling and DHW system.
Installation of water convectors and internet thermostats
At the customer’s request, the heating and cooling of the home is controlled via the Internet. Each room is equipped with a Wi-Fi internet thermostat that controls the operation of the heating and cooling appliances and installations in the respective room.
Floor heating is controlled on the first floor – five circuits and three convectors.
On the second floor, three convectors and one radiator.
In the attic – two convectors.
Water convector with internet control installed in a bedroom
Heating and cooling convector installed in living room
Water convector with internet control installed in another bedroom
Installation of the SAMSUNG 16 kW three-phase air-water heat pump and an Eldom 200 liter water heater with two parallel coils
As the last part of the construction of the entire system, the external body of the heat pump, its internal (hydrobox) body and the enamelled boiler of 200 liters were installed. The necessary fittings are connected around the indoor unit for optimal operation of the installation. Preliminary checks and tests were carried out, after which the Air-Water heat pump was put into operation. The necessary settings for operation in the different modes, heating, cooling and DHW (hot water) were made. The different maintenance temperatures have been set, depending on the different indoor and outdoor conditions, with the aim of optimal and efficient operation, maximum comfort and the lowest possible bills.
Outdoor unit of three-phase heat pump Air-Water SAMSUNG 16kW
Internal (hydrobox) body of a three-phase Air-Water heat pump SAMSUNG 16kW
Enamel boiler Eldom 200 liters with two parallel coils (the heat exchanger)
What is the cost of the entire heating, cooling and DHW installation with a SAMSUNG 16 kW three-phase heat pump?
Perhaps this is the question that most interests you? Most likely everyone, we are interested in this. But before we talk about the price, let’s briefly state what we get for it.
What do you gain with heating, cooling and DHW with an air-to-water heat pump?
- a single system for heating, cooling and hot water – which would be provided with at least two, three other installations
- non-commitment to the system – no loading, maintenance, cleaning, storage, splitting, carrying, stacking…
- one-click control via phone – option
- optimal comfort
- maximum efficiency
- lowest possible heating, cooling and hot water bills
- air conditioned home
- more free time (and time is money) for yourself and your family
- and a number of other benefits that can only be felt if you own it.
What does the whole heat pump system include?
- making the necessary heat loss calculations
- design of the entire installation
- forecasting monthly bills
- checking and guaranteeing the required power
- three-phase heat pump Air-Water SAMSUNG 16kW
- insulated copper riser pipes
- manifold boxes and brass taps and fittings
- enamel water heater 200 liters with two parallel coils
- programmable internet thermostats
- electric actuators to control the floor heating
- mixing unit and collectors with flowmeters for underfloor heating
- water convectors for heating and cooling
- aluminum radiator
- and many, many other small but mandatory items
Now let’s talk about the price, since, fortunately or unfortunately, the entire system was not installed by a single company, the total price is a little higher than normal. According to the client’s data and notes, the total amount for the heat pump installation of the house amounted to BGN 28-29 thousand.
If only one company had participated, the amount would have been in the order of BGN 24-25 thousand, and the price of the SAMSUNG 16kW three-phase heat pump alone is BGN 12,643.20.