SFBF Solar Heating For Radiant Floor Heating Systems

1.1 Overview

• SFBF is a complete system that uses solar energy to heat floor(Solar heating Radiant Floor Heating systems).

• This Hybrid solar radiant heating system is a complete solar heating kit that works with any in floor heating loop or radiant floor system.

• Solar heating system can be combined with any energy source such as gas, heat pump and electricity to form a hybrid heating system that operates around the clock and reduces the cost of use.

• Floor heating system heats the floor by circulating hot water in a closed pipe laid under the floor, and supplies heat to the room through radiation conduction and convection conduction through the ground.

• The entire ground is a radiator, which is conducted from the bottom to the top by the law of the ground's own heat storage and heat radiation, and evenly heats the room.

• Use solar floor heating can save 25%-40% energy.

• Free hot water all over the year.

1.2 Structure and how it works

• SFBF system consists mainly of solar collectors, hot water storage tanks (double coils), solar controllers, circulation pumps, expansion tanks, valve fittings and piping.

• The solar collector（solar panels） collect the suns energy and heat the special solar heating fluid.

• This hot fluid is then piped through a internal heat exchanger found in the bottom of the solar storage tank.

• The heat energy is then transfered to the water storage medium and the hot water rise to the top of the tank.

• The top of the tank contains as second heat exchanger that connects to a second pump on the radiant floor loop.

• Average unit heat dissipation:q=40W/m2.

• Ground temperature for long stays: 24～26℃/75～79℉.

• Ground temperature for short stays:28～30℃/82～86℉.

• Heat medium temperature in the circulating heating line: 40-60℃/104～140℉.

• Hot water flow rate in the circulating heating line: 0.25～0.5m/s(0.8～1.7ft/s).

• Water supply pressure: 0.3～0.5Mpa/40～70Psi.

• Supply and return water temperature difference: ＜10℃/50℉ m.

• Length of each cycle heat pipe: 60～80m/200～270ft, the maximum length should not exceed 100 meters / 330ft.

• Spacing of circulating heating tube: 150mm-300mm/6-12 inches.

• Area of House that needs heating.

• Type of floor material .

• Building wall materials and insulation properties.

• The amount of sunshine and winter temperatures in the city.

• Solar collector installation location.

• Need or not additional hot water for domestic hot water.

• Utilization, connection and intelligent control of original heating equipment.

• Design of an alternate energy system.

• There are many design factors for the solar heating for radiant floor heating systems project, in addition, the seasonal distribution of sunlight is uneven(Good summer sunshine and high water temperature, weak winter sunshine and low water temperature).This requires not only accurate calculations based on the specific conditions of the project, but also actual experience.Comprehensively determine the configuration of the solar heating system, especially the area of the solar collector and the capacity of water tanks.

• The design area of the solar collector is too big, resulting in high investment cost and low effective utilization of solar energy.

• The design area of the solar collector is too small, which will make the consumption of the backup energy large, so that the energy saving effect is not obvious.

• The overall design principle is to meet 55-75% of the use, supplemented with backup energy when the heat is insufficient.

• The amount of heat required for floor heating is calculated as follows:

T for the outdoor calculated temperature of heating.

4.1 solar heating for radiant floor heating systems design case

4.1.1 Design requirements

• The project city: Baltimore, Maryland, US.

• The area of floor heating: 17.7*8.5m（150㎡）/58*28ft(1624ft⊃2;).

• Interior design temperature: 22℃/72℉.

• Alternate energy: Gas water heater(Original equipment).

• Wall Material：Aerated Autoclaved Concrete.

• Roof  Material：Metal, Black.

• Floor  Material：Insulated Concrete Slab.

• Type of Heat - Radiant Floor:1000 ft x 3/4 " (300 metersx 19.05 mm) of PEX tubing in concrete floor slab.

• Domestic hot water: 4 persons.

4.1.2 System design operation diagram

4.1.3 Common specification configuration list

4.2 Solar heating villa floor heating, swimming pool and domestic hot water design case

4.2.1 Design requirements

• The project city: HAUGE DALANE, NORWAY.

• The area of floor heating: 290㎡/3120ft⊃2;.

• Interior design temperature: 20℃/68℉.

• Pool capacity: 10 000  litres.

• Domestic hot water: 5 persons.

• Alternate energy(Original equipment): air heat pump（CS-E18DKEW）+300L tank（Oso EP 300).

• Floor heating in winter,swimming pool heating in spring and summer, and provide domestic hot water all over the year.

• The advantage of this design is that solar energy utilization is the highest, and it is fully utilized throughout the year without worrying about overheating in summer.

4.2.2 System design operation diagram

4.2.3 Common specification configuration list

4.3 Solar heating apartment floor heating and domestic hot water design case

4.3.1 Design requirements

• The project city: Tacoma, United States

• The area of floor heating: 4 floors apartment,160㎡/Floor

• Heat floor heating in winter,and provide domestic hot water in other seasons.

• The backup energy uses electricity.

• The advantage of this design is the use of an unpressuried double coil water tank to reduce costs.

4.3.2 Common specification configuration list

4.4 Optional Accessories

• Solar collectors can be installed on the ground, on the flat roofs or inclined roofs where have efficient sunshine.The brackets need to be fixedly connected with mounting base.

• Water tank（If any） is placed on the ground or on the roof.

• Circulating pump is fixed on the ground or wall and needs to be protected from rain and water.

• Solar circulation pipe is connected by metal pipe, such as red copper pipe or stainless steel bellows pipe. PPR pipe is avoided.

• Solar collector is installed in a symmetrical matrix to avoid unequal pipeline flow and short circuit.

• Heat exchanger（If any) should be installed close to the swimming pool.

Please check here for installation methods and procedures: