Data center air conditioning refrigeration green energy-saving technology guide

With the http://www.aliyun.com/zixun/aggregation/13737.html "> Blade server, Virtualization technology and other large-scale applications, data center density is also increasing." The survey shows that the energy consumption of air-conditioning has accounted for nearly 40% of the energy consumption in the room, which means that the data center refrigeration system has a lot of energy saving space.

This paper mainly introduces the energy-saving methods of the refrigeration system in the data center, including how to improve the energy-saving characteristics of air-conditioning system through technical renovation, and introduces some energy-saving tips in refrigeration.

Improving air conditioning performance and realizing green energy saving by technical renovation

At present, the use of air-conditioning systems, early products in the advanced aspect compared to new products will have obvious deficiencies, through technical transformation, can improve performance. The measures that can be taken are:

1, the use of high energy efficiency of the compressor, such as scroll compressor.

Air conditioner Compressor is the "power of the Heart," for air-conditioning, the most important factor to determine the quality of the compressor, the first to buy air-conditioning to see the compressor. Air conditioners mainly include compressors, condensers, evaporators, four-pass valve key, and in these four major components, to the compressor is the most important. Air conditioner compressor is the power core of air conditioner refrigeration system, it can be inhaled low temperature, low pressure refrigerant vapor through compression to improve temperature and pressure, so that the refrigerant inside to move up, and through heat conversion to achieve refrigeration purposes.

The performance of the air conditioner compressor determines the energy efficiency ratio of the air conditioner. Energy efficiency ratio is the ratio between air conditioning refrigeration capacity and refrigeration power. The energy efficiency ratio of air conditioner is divided into 5 levels, 1 is the most energy-saving, 5 is the most energy-consuming. Industry experts suggest that the choice of energy-saving air-conditioning first consider energy efficiency ratio.

There is also a point to note, air conditioning compressors with frequency conversion technology, energy-saving effect is better, the choice of energy-saving air-conditioning should be used as far as possible to choose frequency. Inverter air conditioner compressor motor speed variable, to avoid the frequent start-up of compressors, and fixed-speed air-conditioning compared to electricity saving 30%.

2, the use of ethylene glycol solution as a cooling agent to the internal cooling working principle.

In the whole air system, it is not easy to realize the air conditioning method of cooling tower to the inner area for the cold time in winter. At this time, outdoor cold air can be used as a cold source, ethylene glycol solution as a refrigerant, the outdoor natural cold into the interior for the cold. Need to heat the outside area to the inner zone for cooling, close the chiller, still use boiler or city hot water as heat source to the outside district heating.

In the outdoor installation plate heat exchanger, by the fan will be outdoor cold air into plate heat exchanger, ethylene glycol solution and outdoor cold air in the plate heat exchanger heat exchange. The cooled ethylene glycol solution enters the inner area of the air-conditioning unit, in the unit and mixed air (the new, return air after mixing the atmosphere) for heat exchange, the mixture of air is cooled, the temperature lowered into the inner zone room, to the inner area room for cold. Ethylene glycol solution temperature rise, again back to the outdoor plate heat exchanger, with outdoor cold air for heat exchange, temperature reduced and continue to cycle. This heat exchange method is often used in heat recovery systems. Ethylene glycol and high-temperature exhaust heat exchange, temperature rise, into the new air cabinet, to preheat the fresh air. Thus, the recovery of heat from the exhaust wind to the fresh air heating, saving electricity, save operating costs.

It is a kind of energy-saving air conditioning method to introduce the ethylene glycol solution as the refrigerant, and the cold in the outdoor cold air to the inner area for cooling. Only in the outdoor installation of a plate heat exchanger, running, chillers closed, only open fans and air-conditioning units can introduce natural cold to the inner zone for cooling, saving energy, reduce operating costs. However, in the use of outdoor cooling in the process of cooling to the inner zone, cold air to heat exchange with ethylene glycol, ethylene glycol and mixed air heat exchange, after two heat exchange, cooling loss of large, heat transfer efficiency is not high, generally less than 60%.

3. Variable speed motor.

In fact, many room air-conditioners are overdone. Because most of the room air-conditioning is very primitive, either open, or off, can not adjust the size of the current only 10% of the room air-conditioning with variable speed motor. The air conditioner with variable speed motor can adjust the size of air-conditioning according to the need, so as to achieve energy saving and consumption reduction.

4. Other.

There are also technologies that can make the data center's air-conditioning more energy efficient. such as the proper amplification of the condenser, increase the heat dissipation area, reduce the condensation temperature, increase the refrigeration coefficient, add the frozen oil additive, reduce the impedance mill, enhance the condenser and evaporator heat transfer; in summer, the wind-cooled condenser is shading, water mist cooling and other measures, that is to reduce the high pressure jump machine failure, but also energy saving; Computer automatic control of the working state of air-conditioning, according to the ambient temperature and humidity, automatic accurate change settings and so on.

Green energy-saving refrigeration scheme and tips

Attach importance to Airflow organization

For the large span of the room, air conditioning system with the return of the wind should also have the wind duct or ceiling air return, not only the temperature field and speed of the bar field uniformity is good, and energy-saving effect is also good. In addition to some of the more high-density cabinets may have 20-kilowatt or 25-kilowatt such some can take a number of direct cooling source of the air supply mode. Another can be fitted with a special device to let it blow in.

Use natural cooling

Winter or part of the spring and autumn season, the outdoor air temperature is low, room indoor air temperature is higher, still need to provide cold. In particular, there is no external wall, outside the window of the room, due to the equipment in the room's continuous heat dissipation is not distributed to the outside, indoor still need to provide cold. Because the cold load is small, the cooling coefficient is low, the energy consumption is big, if the cooling machine is open to cold is unreasonable. In fact, nature is the best cold source, not only do not need to obtain energy, but also adequate supply, belong to green cold source.

Natural cooling is the technology that does not use cooling equipment or compressors to cool air. The amount of natural cooling available depends on the local climate, with a natural cooling range of approximately 100 hours to 8,000 hours per year. Two of the most common natural cooling methods are groundwater or surface water cooling and outdoor cold air cooling.

1. Groundwater or surface water

The groundwater is kept at a lower temperature all the year round, and the formation temperature below the surface of the 5~10m is not changed with the change of the outdoor atmosphere temperature, so the groundwater can be used as the cold source of the air conditioning system. However, recent studies have shown that the excessive exploitation of groundwater has a great impact on ground subsidence and threatens the future freshwater resources of the whole country, so it is not recommended to use groundwater at present. Surface water including river, river, Lake and so on, in spring and autumn or winter, as long as the surface water above freezing point, can be introduced through the pipeline as a cold source.

2. Outdoor Cold air

Spring and autumn and winter outdoor air temperature is low, can be used for air-conditioning system cooling. Considering the air directly into the computer room, easy to dust and other harmful things into the room, you can use indirect cooling method to solve. For example, with economic coil special air-conditioning winter operation, the use of cooling towers for cold, with fans of the window-type heat exchanger, the small room using heat pipe to the cold volume into the room and so on.

Group control of Precision Air-conditioning network

In the room of the precision air-conditioning there is a competitive operation of the situation, each air-conditioning position is not the same, affected by airflow, air-conditioning operation is not the same, some air-conditioning in refrigeration, some air-conditioning is generally in the low temperature of the situation under the antipyretic, and some in humidification, some air-conditioning in dehumidification, how we deal with their running state, Make them run effectively?

Multiple units through the communication cable can realize the group control function, the network unit can achieve the main standby switch, round Patrol, Cascade, host alarm/Power off standby machine start-up functions.

The benefits of group control mainly include: Operating efficiency multiple units communication network work to improve the overall efficiency, the competition between the unit is avoided; multi-unit communication network work, optimize the temperature and humidity control accuracy, multi-population control method can meet the requirements of various application sites. These end up with data center energy saving, security, and unit life extension.

The main group control controller and its suitable scene: Icom controller group control, suitable for PEX air-conditioning; PACC Controller Group control, applicable to CM and pan-brand air-conditioning; AC4, AC8 controller, suitable for all brands.

Reasonable control of indoor temperature parameters

For a long time, for safety, energy-saving and other considerations, for the computer room temperature setting should be the upper limit, the lower bound value or with the seasonal adjustment, has been a great controversy. Because of our vast territory, the situation varies from place to place, so this problem must not be generalized. But the room temperature increase, for energy saving is obvious effect, and this energy saving is not required direct economic input that has output.

IDC room air-conditioning set temperature is generally 21--25℃, individual room air-conditioning temperature control is very low, or even low in 20 ℃, very wasteful energy, therefore, the rational setting of the temperature of the room air-conditioning is particularly important. Recently reported abroad, with the upgrade of the server function, IDC room temperature can be 28 ℃. Check the performance metrics of some servers, the inside of the chassis temperature below 40 ℃ can be normal operation. Therefore, our current more stringent room temperature requirements are still questionable. Before we have a clear new standard, it is reasonable to set the temperature higher in summer and lower the winter setting.

Reasonable to improve the temperature of the computer room has the following energy-saving effects and advantages:

1, reduce the indoor heat temperature difference, so as to reduce the heat transfer of the enclosure structure of air-conditioning load;

2, can reduce the air conditioning load formed by the fresh air;

3, the air conditioning evaporation temperature corresponding increase, the refrigeration coefficient enhances. It can reduce the demand of peak load and save the electricity consumption.

The experiment proves that the energy-saving effect under different indoor temperature is different, the energy saving is 18% when the indoor temperature is increased 2 ℃, and the energy saving is increased 4 ℃. For the computer room set temperature increase after the energy-saving effect, although there is no very authoritative data, but there is an increase of 1 ℃ temperature about can save air-conditioning power consumption 2%~5% conclusion.

Install the sensor to observe the temperature at any time

Place a small number of individual sensors where there is a potential temperature problem. Simple sensor-stored temperature data can be manually collected and transmitted to a form file for further analysis. Even this small amount of investment in equipment can well see the dynamics of data center temperature problems, providing an analytical method for improving data center cooling.