The discussion on performance of the solar energy water heater device

So far, the research has focused on the performance of the water heater on the heater, the determination of the entire performance is more for water heater system

Less. Heat exchanger is a key part of the water heater device, intensive research is undoubtedly important to it. But on the other hand,

For the determination of the overall performance also nots allow to ignore, because it embodies the final water heater use effect.

Measure the performance of water heater, and units produced by each manufacturer by the user is not unified, some see the highest water temperature value, some look

Using the length of the month or the size of the water supply, the most commonly used is the so-called \"daily average thermal efficiency\", it is to point to in the day can be collected

Quantity and projected onto a heated pervious to light the ratio of surface energy. But the thermal efficiency is an important feature, is it in different meteorological conditions and luck

Have different values under the line parameters, and differ significantly. Obviously, with such indicators to assess the performance of water heater system,

Especially used to compare the advantages and disadvantages of different water heater system q is not scientific.

Water heater system thermal efficiency numerical uncertainty is not accidental, this is because in the operation's performance will suffer more

Caused by uncertain factors, the level of the operating temperature of the water heater and homestead meteorological conditions at that time. Such as season, solar radiation intensity,

Atmospheric transparency, air temperature and wind speed and direction is such factors. But not affect the performance of all factors is more

Change. Factor is belong to the water heater is inherent in the system itself, relatively stable, such as the material of heat exchanger and the structure, adopt hot plate

Surface absorption and emission performance of radiant energy, the penetration performance of transparent cover plate, the thermal conductivity of insulation materials used and the total system

Heat transfer coefficient, etc. The second factor mainly depends on the water heater system arrangement and cooperation scheme, such as water heater's geographical location, mining

The azimuth and Angle of the heater, the relative capacity of storage tank, etc. A water heater system in performance is showed in the operation of the above three categories

The results of all kinds of factors.

We think that, as the performance index, mansion for a given water heater system with relatively stable value; Should be in the given conditions F

Its performance; Should be possible to become a common standard for evaluation and comparison of various kinds and types of water heater system technology

The level of high and low. Such performance metrics used to be a problem, but in recent years on the water heater system dynamic characteristics mathematical description of research

Investigate, butyl theory basis for scientifically this specification. Based on analyzing the essence of the system operation characteristic, this paper put the water heater

System inherent in the relatively stable factors together, to mount the concept of \"system characteristic factor\", which is defined as:

The first characteristic factor x = F (wenger) cH. / U (useful one (1)

Held the second sign factor Y = F (M) (2) the eCe/C

Parameter 2 = C (2 a/b Ho qiao (3)

The second part of this article will explore system characteristic factor experiment measurement problem. As is known to all, adopt heat exchanger performance of formal measurement needs

Special circuit and essential for some special equipment and instruments. We do not need special test method introduced in the test circuit, no

Need constant pressure water tank and flow meter, also do not need heater, cooler device such as a constant temperature, but the water heater is installed in the system

Use less as far as possible the instrument on the determination of the characteristics of the factor.

Finally, we used the measured characteristic factor combined with 2 parameters and meteorological data to calculate the daily operation curve and water heater system

The measured data are compared.

We analysis the object is natural circulating water system of no load operation condition. Of course, from the viewpoint of the basic idea,

Other forms of water heater system is not yet using for reference.