On the eco-friendly low-temperature radiant floor heating

Paper Keywords: low temperature radiant floor heating, environmentally friendly energy saving heating methods
Abstract: The low temperature hot water radiant floor heating characteristics, analyzes the technical and economic advantages and disadvantages of the construction process needs attention.

Introduction
In recent years, people living increasing demand for comfort, but energy efficiency is very low, the rapid growth of building energy consumption has been greatly exceeded the growth rate of energy, building energy consumption ratio of total energy consumption is close to 30% only one heating energy consumption, total energy consumption already accounts for about 10%, energy shortages and economic development has been severely restricted, affecting people's living standards improved. Currently, most urban residents in northern China using convection heating radiator , low temperature radiant floor heating in recent years began to households. temperature radiant floor heating is not a new heating technology, foreign began in the early 20th century used in some projects, but prone to corrosion of metal pipes and seepage leakage and other issues, this heating method has not been growing rapidly. until the 20th century, 70's, "plastic steel" technology and the emergence of polyethylene pipe, making the low-temperature hot water radiant floor heating to life.

A low temperature radiant floor heating
With the continuous improvement of living conditions, people also set new indoor heating requirements. Many projects using low-temperature radiant floor heating system to replace the traditional radiator heating, to overcome such as energy consumption, comfort is poor, difficult to sub-metering, issues such as use of the area occupied by the room. low temperature hot water radiant floor heating is a ground for use inside the building heating system that will place plastic pipe laid in the floor concrete layer, the hot water temperature �� 60 ��, working pressure �� 0.4MPa. The system as a cooling surface of the ground, floor heating in the ambient air by convection, it is also with the human body, furniture and maintenance of the structure around the radiation heat transfer, making it the surface temperature, its radiation heat exchanger for about 50% of the total above is an ideal heating system, radiator heating can effectively solve the problems. low temperature hot water radiant floor heating to save fuel, low power consumption, is the most economical heating system.

1.1 comfort, health, health care
Conventional heating radiator heat concentrated in the upper part of the room, the heat under the cool, people have the feeling of dry mouth. The low-temperature radiant floor heating is a way to heat evenly, this is the most comfortable way of heating, indoor uniform surface temperature, room temperature gradually decreasing from bottom to top, giving the feeling of cool head and warm feet, in line with "warm enough to cool the top" theory of Chinese medicine fitness can improve blood circulation, promote metabolism. Meanwhile, the main mode of heating radiator relying on natural convection heat transfer, due to high temperature heat source, and thus a larger air flow rate; and radiant floor heating and natural convection mainly depend on heat transfer in two ways, using low temperature heat medium, avoiding the strong convective heat indoor air exchange, air flow rate is low, greatly reducing the dust generated by convection of the second indoor air pollution. Because wind is an important factor affecting indoor dust, so dust the room with floor heating is very small, more hygienic, improving the home- environment.

1.2 beautiful, do not account for use of the area
Indoor various pipeline structure can be laid in the warm layer, the legislature removed the radiator, pipes, not only increased the use of space, and the room can be arbitrarily separated for easy decoration and furniture.

1.3 noise insulation, thermal stability
At present, the use of prefabricated panels compartment floor, or place the general board, its texture, brittle, poor sound insulation. Floor heating due to increased insulation, can significantly reduce the noise in the upper to the lower deck, with a very good acoustic insulation. Since the ground to warm the special structure, when the upper and lower layers without heating, the middle layer of the heating effect is almost not affected; the ground floor and a concrete layer heat storage capacity, which in the case of intermittent heating, indoor temperature changes slowly, the thermal stability good. radiant floor heating because thick layers of concrete and mortar as the heat storage structure, system, regenerative ability, and therefore greater thermal inertia, thermal stability, strong resistance to outside interference. Therefore, even in the intermittent heating conditions, the room temperature fluctuation. tests showed that at room temperature to stop heating at 20 ��, 12h after the temperature still maintained at around 18 ��. reposted elsewhere in the Research Papers Download http://www . hi138.com 1.4 energy-efficient, low operating costs
Usually 95 for a radiator heating water temperature of 70 �� and requires a lot of heat. The use of radiant floor heating the heat medium temperature is low, some low temperature heat source can also be used, such as solar, geothermal water. There is also the use of thermal power plant heat, urban heat supply network and other energy backwater. The effective use of low temperature heat source, not only to save a considerable amount of non-renewable resources, while reducing emissions, waste emissions, both energy and environmental protection. floor heating system to achieve the same comfort conditions in premise, the indoor design temperature heating than other forms of energy can be reduced by 20% to 30%, improved thermal efficiency, and the room temperature can be adjusted independently.

2 low-temperature hot water radiant floor heating construction
2.1 radiant floor heating pipe
Commonly used in radiant floor heating pipes are steel, copper and plastic pipes. As the plastic pipe with no joints, easy to bend, easy construction, etc., which are widely used in engineering. Commonly used plastic pipe are: cross-linked polyethylene PEX pipe , a C Polypropylene PP pipe, polybutylene PB pipe, cross-linked polyethylene plastic composite pipe XPAP so, they have anti-aging, corrosion, scaling, high pressure, no pollution, easy to leak , water resistance and other characteristics of small thermal expansion coefficient at 50 �� environment, with up to 50 years. Regardless of the pipe, tube and pipe outer wall should be flat, smooth, no bubbles, nicks, cracks, peeling and obvious scar patterns, depression; pipe fittings and pipe should be the same color, uniform color; handling, transportation should be handled with care, not by the violent collision and the impact of sharp objects, can not throw, throw, roll, drag, avoid contact with oil; in the storage and construction process, to prevent dirt and debris into the tube, stored at should avoid direct sunlight.

2.2 low-temperature radiant floor heating pipe laying method
(1) Vertical: With the water temperature is gradually reduced board, the temperature difference between head and tail, the board surface temperature field uneven.

(2) rotary and reciprocating types: the laying of complex, high-temperature tube spacing layout, the board temperature uniform heating effect is good. Each branch loop is generally 60 to 80 m, the longest should �� l20m, in principle, take a room in a loop, large area of ​​the room to expand the 20-30m2 a ring; each loop should adopt the entire root pipe in the middle does not allow a joint to prevent leakage; close to the wall, outside the window at the hot loss of large distance between the heating coil should be furnished with a small number, in order to maintain the department's surface temperature.

3 current problems in radiant floor heating
(1) radiant floor heating need to increase the thickness of the floor, so that decrease in height of the room, but also increase the floor load, making the cost of civil engineering. Given under floor heating piping in the floor, and the thickness of the ground compared to ordinary heating an increase of 6 for a 9 cm, the design should be considered an appropriate increase storey to ensure the effective clearance of the room.

(2) indoor furniture and other items arranged on the floor of the block, will affect the low-temperature radiant floor heating the heat, particularly small bedroom room should carefully consider the thermal effect.

(3) The floor heating thermal inertia, lack of capacity of its rapid heating, it normally takes 1 .5 h before to meet the design temperature.

(4) As the heat to warm up from the floor, easily lead to filling layer, the leveling layer of concrete shrinkage, resulting in thermal stress, resulting in cracks in the ground slightly.

(5) to poor maintenance. Radiant floor heating works are hidden, if pipe leakage, its maintenance is difficult, requires the use of specialized equipment for leak detection and repair.

4 Conclusion
Low-temperature radiant floor heating, as a new heating system, "plastic steel" technology breakthrough, after the limitations of metal pipe, in many developed countries has been widely used, but still in the initial period in our country. Temperature radiant floor heating with good energy saving effect, residents can create healthy, comfortable and environmentally friendly indoor environment, the future development direction of building heating and has broad application prospects. Links http://www.hi138.com Research Papers Download