Why do you say that the air-source two-generation co-generation ≠ air-cooled heat pump cold and heat module machine?
Both the air-cooled heat pump cold and heat module and the air source heat pump have two functions of heating and cooling, but they are not completely the same. The air source heat pump heating units that have received a lot of attention in the past two years are also different from air-cooled heat pump cooling and heating modules and air source heat pumps. In this paper, the specific differences between the three types of products are analyzed in three aspects: product implementation standards, design conditions, and component selection.
One. Different design execution standards
The implementation standards of different products are shown in Table 1. The above implementation standards can only be used as a reference, that is, the standards that are generally referred to when testing for third parties. In practice, manufacturers consider the possibility of using radiators for heating when designing products. Therefore, air source heat pumps The heating unit and the air-source heat pump combined supply unit will exceed the national standard in terms of water temperature and reach 55 ° C or higher. The air-cooled heat pump cooling and heating module generally does not exceed 50 ° C, so it cannot be used for heat dissipation. Heating place.
In fact, for the air-source heat pump two-generation unit, the market is generally divided into low temperature machine and normal temperature machine according to the area of use. The low temperature machine also refers to GB / T25127.1 or GB / T25127.2 normal temperature machine reference table. Column.
two. Different design conditions
In terms of design principles, these three products all follow the inverse Carnot cycle principle. The air-source heat pump heating unit emphasizes low-temperature heating performance. In order to achieve low-temperature heating performance, the technology used is jet enthalpy technology, which can also be used. Compressor variable speed technology also uses two-stage compression technology, and even heating technology using transcritical refrigeration cycles. Therefore, according to the technological examples, cost control capabilities and market control capabilities of each company, decide which technology to use to achieve low-temperature heating performance and m / p of the unit.
In the same way, the two products of the air source heat pump combined supply unit and the air-cooled heat pump cooling and heating module unit have different application areas and functional focuses. Generally, the principle of the first-stage reverse Carnot cycle or the variable speed technology of the compressor is used. Of course, According to the market considerations of various companies, in order to increase the competitiveness of products, the technology of air source heat pump heating units will also be used. But all the units follow the principle of reverse Carnot cycle of vapor compression.
From the design conditions, the air-source heat pump heating unit emphasizes heating more. The heating characteristic is to be reflected in the heating effect and heating energy efficiency of the unit in a low temperature environment. The manifestation is mainly a horizontal comparison. The advantages of gas boilers, coal boilers, electric heating, etc., so from the design reference standard, the GB / T25127.1 or GB / T25127.2 standard is adopted, and the ambient temperature of -12 ℃ is specifically required to Nominal; the other two products, in terms of breadth, are larger than heaters, mainly reflected in the use of GB / T18430.1-2007 or GB / T18430.2-2008 standards (of course GB / T25127.1 or GB / T25127.2 standards can also be used. These two products are more concerned about the performance of cooling and take into account heating. In the case of satisfying the cooling performance, if the heating cannot meet the use conditions, it is generally supplemented by the use of auxiliary electric heating.
It should be noted that the air-source heat pump two-generation unit is mainly based on the implementation of normal operating conditions. If it is performed in low-temperature environment, it can be classified as an air-source heat pump heating unit.
From the end of use, the end of the heating of the air-cooled heat pump cooling and heating module is generally a fan coil, which has strong convection heating. The air-source heat pump heating unit and air-source heat pump combined supply unit not only meet the fan coil control heat, but also In order to meet the heating method of the floor heating pipe with the full radiation method, the air source heat pump is more strict in the design conditions and the water temperature, and the temperature control accuracy is also relatively stricter. Therefore, the air-source heat pump combined supply unit is more resistant to high pressure, high pressure difference and high temperature than the air-cooled heat pump.
From the perspective of electrical control design, the electrical control design of the three products is basically the same, and generally no special requirements are made.
three. Different parts selection
From the current stage, in addition to the traditional “four major pieces” of air source heat pump heating units, in general, an intermediate economizer or a flash evaporator will be added to do each part of the secondary compression circuit. The other two products are generally only "Four Big Pieces". However, due to the improvement of low temperature performance, many new technologies are added or several technologies are used in combination. For example, a regenerator is also added. Especially for the two-stage compression technology, the circuit is completely different from the traditional one-stage compression. It is also difficult here. In one word.
The knowledge in Table 3 compares the differences between the three mainstream products in the current market, that is, the standards they refer to are different, and the standards for some component products are different, but in general, the three products will tend to be the same or unified.