Weak current College】 【VRV system.

1. Introduction to conditioing
The full name conditioing, namely for VariableRefrigerantVolume system variable refrigerant flow system. System structure similar to the split air conditioning units, with one outdoor unit corresponds to a set of indoor unit (usually ranging from 16). Control technology, adopting Inverter control mode, press the number of open indoor machine control of outdoor machine speed, scroll compressor for refrigerant flow control.
Conditioing and full air system, water systems, air-water system compared to better meet user requirements, personalized device occupies building space is smaller and more energy efficient. It is because of these characteristics, it is more suited for those who need to use the regular independent overtime office building construction project.
VRV system consists of two parts: the air conditioning equipment and air conditioning pipe design; design of air conditioning system control, the first part of the content from the design of HVAC engineers design Institute, part of the content is usually made with a full range of products for systems engineering contractor matching design.
Second, VRV systems control
1.VRV general control of air conditioning systems
This control is relatively simple, each corresponding to a number of outdoor unit (usually up to approximately 16) indoor unit, the Group conditioing are independent operation control, in-place remote control settings can be used by the project realization is a remote control corresponds to an indoor unit, or a remote control for the corresponding number of sets of indoor unit, is a relatively economical and practical way of control.
The control methods are end-in-place control without the centralized monitoring and management, in actual use, indoor temperature value sets, power-on time, on a large number of arbitrariness, the use of the flexibility, convenience is often at the expense of sacrificing power, from a pure energy perspective effect is not evident.
2.VRV centralized control of air conditioning systems
Configure a separate control management systems control, and is currently the VRV system uses the control mode, increased concentration control management link, you can control the indoor on remote systems VRV group monitoring and management, is a perfect way of control, but investments increased significantly.
Shown in the figure of the control programme, can according to user's use of the scale, investment capacity and management requirements. This programme is of deficiencies and building other weak electricity system no features, especially in intelligent building design, is not conducive to the weak electricity system features integrated.
3.VRV air-conditioning system gateway control
For an already designed the building automation system (BAS), intelligent building, how reasonable, maximize their system features that reduce the system equipment of repeating investment, improve system integration technology ability, is the author here focused discussion with members.
Building automatic control system is important in the intelligent construction equipment, from the usual monitoring objects, on the air conditioning system of monitoring terms of monitoring points representing the number of system-wide or from input-output comparison of energy-saving effect, throughout the system are an important weight, building automatic control system of the other part of the principal amount of time for the switch, the event monitor signal. In adopting the VRV systems for intelligent buildings, if not incorporated in the structures of the building automation management system, the entire system for energy efficiency will be reduced and equipment payback growth, economic benefits will be reduced.
In order to achieve these design ideas, the author has a project of building automation system design reserved number of input, output, control points, with a view to VRV system health monitoring. Later discovered since conditioing of indoor and outdoor machine is a closed-loop control system, and the outdoor unit is always in paternity suits or running that set in the traditional way of building automation monitoring and control points appear to lack of practical significance, the only consideration is, in its distribution circuit monitoring node in the set, press set time program, open the system control unnecessary waste of energy.
After conditioing control product visibility and found quite a lot of VRV product manufacturers have been developed based on the BACnet protocol dedicated gateway interface device that can meet the author conditioing into buildings, building automatic control system.
VRV terminal equipment running through BACnet gateway interface upload signal to building automation Center of BAS or BMS systems, automatic control centre via the gateway interface download signal (such as the initializer, control parameter settings, etc.) to terminal equipment and to implement the entire conditioing systems management. After this second system integration in the central control center can VRV system:
(1) room-temperature monitoring
(2) thermostat status monitoring
(3) compressor operation status monitoring
(4) indoor fan operation status
(5) air conditioners exception information
(6) ON/OFF control and monitoring
(7) temperature setting and monitoring
(8) air conditioners mode setting and monitoring (cooling/heating/fan/automatic)
(9) on the remote control mode setting and monitoring
(10) filter signal monitoring and reset
(11) wind direction setting and monitoring
(12) rated air flow setting and monitoring
(13) forced shutdown setting and monitoring the temperature controller
(14) energy efficiency sets and set state monitoring
(15) set/machine controller action reject and monitoring
(16) the system of forced shutdown setting and monitoring
Configure a separate control management system of control, based on the BACnet protocol gateway VRV system control lines on the form from the controls belong to the centralized control and management, as Figure 3 control mode is based on building integrated intelligent control and management platform, and other weak electricity system implementation linkage control functions, its superiority is even more obvious. Such as the use of electronic attendance and electronic lock system implementation conditioing KaiAnd linkage, the purpose of achieving effective energy conservation, the use of fire alarm signals, the implementation of the corresponding conditioing, meet fire linkage function. </P>
Third, VRV system of BACnet gateway interface
While emphasizing the product and system of open interoperability of today. BACnet building automation system as an important standard, in recent years has been the general concern for people. The development of some equipment can with a number of "third party" device compatible communications, but there is still a lot of the equipment in a custom communication protocols, you can only use the gateway with the "third party". VRV system of BACnet gateway is a manufacturer to achieve their air conditioning systems and building automation systems for Internet and design of the private network interfaces, it is available through the BACnet Ethernet LAN and BACnet client communications. Support BACnet conformance category 3. Support the application of the portions of the BACnet standard. Support some of the standard object class, which provides information on VRV system. Currently, this type of equipment essential to the market's leading building automatic control system devices implement connection, such as HONEYWELL, SIEMENS, etc YONNSONCONTROLS and brands.
IV. use of BACnet gateway economic comparison
Using BACnet gateway interface to set the smart way to manage the device-independent manner compared to meet similar functionality, hardware device under conditions of low investment, software functionality is similar. Therefore, the total investment cost is low and the implementation of the function is complete. But a simple remote control also need to increase the number of charges. From consulting to the gateway to the initial price is about $ 15 million. Exactly how to measure the value of the investment of the device, you can compare two aspects, one is the system of total investment, the second is to achieve its functionality. In General, conditioing investment price is normal air-conditioning system 1.5 times, size of 256 indoor (Office area 5000M2) investment budget is approximately $ 272 (usually a gateway maximum 16 outdoor unit and 256 indoor unit). By contrast, the gateway of the investment costs would make the air conditioning system with a total investment of around 5.5%, with the expansion of the scale of air conditioning systems, control and management software costs unchanged, the control device of the investment proportion will also decrease. To each indoor unit conversion, to each indoor unit about increased investment costs less than $ 600. The author has had landlords require designed a air-water system in the form of air conditioning systems. All Terminal air blower plate Tube are respectively used networking interface mode, each interface works quoted at $ 1000, which is compared to the end of the monitor, relatively speaking VRV system uses the Gateway pattern is relatively cheaper, not including 16 outdoor machine monitoring, using the traditional monitoring mode, the market quotation should not be less than 10 million. For gateway added features as mentioned above, is not a general discrete monitoring can match.
5. conclusions
By conditioing control approach, basically it can be concluded that the control has its place of application, on a smaller scale conditioing, on-site remote control mode is more appropriate. For larger systems, centralized management more reasonable, for building automatic control system of building, priority should be associated with a private network, not only can meet the management requirements, and can take full advantage of building weak electricity smart control management integration platform and a number of weak electricity system implementation function linkage.