【 Weak current College 】 data center energy efficiency

— — Based on the public building energy-saving design standards of

【 Summary 】 national standards for the public buildings energy conservation design standards "GB50189-2005 is the main basis of building energy-saving design and guidelines, data centres dependent on the building, since the data center construction and operation of features, data center energy efficiency is bound to contains the topic of energy efficiency in buildings. This article in accordance with the public building energy-saving design standards on the energy efficiency of buildings, several aspects of data center building energy-saving design and construction of heating, air conditioning, lighting, energy saving and energy-saving measures.

【 Words】 building energy-saving data center engineering works

1 the energy regulations and norms

Resource conservation is the basic policy. In recent years, the country will save the resources especially energy promulgated a series of laws and norms, such as: the People's Republic of China Energy Conservation Act (2007 NPC thirtieth meeting of amendments), the public building energy-saving design standards "GB50189-2005, the building energy-saving project construction quality approval standard" GB50411-2007; the architectural lighting design standards "GB50034-2004.

Energy (energy saving) refers to strengthen energy management, technically feasible and economically reasonable, and environmental and social measures of affordable, from energy production to the consumption of each link, lower consumption, reduce losses and waste emissions, suppression, effective and rational use of energy.

The public building energy-saving design standards "GB50189-2005 implementation of the enactment of the public building energy consumption mainly reflected in the building envelope, as well as heating, ventilation, air conditioning and lighting energy consumption, will improve the building's envelope insulation, etc. to improve thermal performance; heating, ventilating and air conditioning system for the promotion of energy efficiency ratio; lighting equipment efficiency. In that same indoor environment parameters, using standards-compliant building energy-saving design of buildings and energy-saving measures has been taken of the building, as total energy consumption should be reduced by 50%, of which: retaining structure sharing energy saving rate of about 25 per cent to 13 per cent; air conditioning and heating system share in the energy-saving rate is about 20 per cent to 16 per cent; lighting equipment sharing energy saving rate by about 7 per cent to 18 per cent. Thus, in accordance with the public building energy efficiency standards for energy-efficient design objectives and requirements, energy-saving potential and the effect is very significant. Countries the public building energy-saving design standards "is the present main building energy-saving design and guidelines.
　　
2 data centers feature features

Data centers typically refers to a physical space (which can be either a building or part of a building) for data information of centralized processing, storage, transmission, Exchange, management, and computer equipment, servers, equipment, network equipment, communications equipment, storage equipment, etc. are usually considered IT critical data center equipment. Data center infrastructure refers to ensure the data center's IT critical equipment and devices safe, stable and reliable operation and construction of associated infrastructure engineering (computer engineering), data center infrastructure construction objective is for the data center's IT critical equipment operational and data information security, providing 24 x 7 protection of the environment.

In the data center, to business and information processing requirements, IT usually needs to carry key equipment 24 × 7 operation, run IT to critical devices, consume large amounts of electrical energy, a large amount of heat produced, in order to keep IT running in the key equipment of environmental requirements, and needs through infrastructure devices (precision air conditioning devices), to maintain IT on key equipment (temperature and humidity) environment, then the precision air-conditioning refrigeration and consume a lot of power. At the same time, the data center is housed in a building of the thermal envelope of performance, but also directly affect the indoor environment (temperature, humidity). In addition, operational and maintenance processes of management effectiveness, and impact of data center energy consumption.

Data center energy efficiency in recent years gradually parties are becoming more and more attention to a matter that is also a country requirements of important trends. Data center energy efficiency, relative to other energy types, mainly reflected in energy savings and utilization.
　　
3 overall design approach and measures of energy saving

Data Center construction, the overall design is the basis for building requirements, laws and regulations, engineering standards, the use of next-generation data center design and implementation of technology that determines the overall data center construction, the overall framework of thought and technology policy, to achieve the goal of energy-saving construction goals include.

Data Center construction in overall design, mainly from the TCO, total space planning and reasonable airflow construction, systems integration, and so consider energy saving and energy-saving measures.
Data center of the building as a project of construction investment, operating costs are also needed. Data Center construction project TCO contains construction period to the operational phase of the total cost, including: facility construction costs, equipment system cost, software system cost, maintenance costs, daily operational costs, the cost of human resources, etc. In existing data centers daily operational costs (mainly energy costs) accounted for the total cost ratio is increasing trend, the overall design of data center requires attention to the rationality of engineering design in advance and applicability, fully considered in the construction and operation phase, lower data center daily operating costs-energy costs, reduce Datacenter TCO to improve data center efficiency than the economy as a whole.

Data Center can be a building or part of the building, including host housing, support area and auxiliary rooms, and other functional areas. Data Center and rational planning, space and layout is based on the overall design of the construction requirements of the first step is an important step in the overall planning, determine the scale of the data center and system components, the space and layout to determine the room spaceSeparated, work processes, as well as the construction process. Existing data center room sealed sliding types, big space, less partition, suitable space volume (high, clear height, storey), human-computer zone separation, regional centralized monitoring, etc., are all next-generation data center space and layout are advocating design concepts and energy policy.

Data Center layout, host IT within the room key equipment for the regional housing should focus on the layout, and other support areas and auxiliary room indoor temperature and humidity required similar room layout should be adjacent. In the data center IT critical equipment area layout, key equipment under IT, system group characteristics, equipment of calorific values, density, Cabinet equipment layout and cabinet cooling equipment etc., reasonably consider room area, Cabinet column groups, the Cabinet interior of the three levels of precision air-conditioning cooling airflow. Including the location of air conditioning equipment layout and sent back to the wind, air, back to the Tuyere settings, etc. Use the "cold end" and "hot tip" sent back to the wind channel, balance and hash high-density Cabinet equipment layout, and so are the main energy-saving air distribution strategy.

From master planning, space and layout of the building design, power distribution, HVAC design, critical systems and to other ancillary system design. Need to consider the system and the construction of the fusion between systems (appropriate system integration), which can increase data center construction of overall performance and effectiveness.
　　
4 architectural approaches and measures of energy saving

Typically the data center as an architecture (as the minority, such as: IDC or large enterprise data centers) or part of the public building (for the majority, accounting for public buildings in a local area). In the data center through precision air conditioning devices run to ensure that the key to the operation of the equipment IT needs specific temperature and humidity environment, so that the data centre building construction of the thermal characteristics of sliding types is a precision air-conditioning equipment effectiveness of important factors is the focus of energy saving.

Envelope refers to building walls off the surface, such as walls, roof, floors, doors and Windows, etc. Envelope points of non-transparency of enclosure structure (walls, roof, floors) and transparent envelopes (glass doors, glass curtain wall). Thermal bridging refers to the temperature difference between both sides in the envelope, form the heat flux density of heat transfer area.

Typically, the characterization of the building envelope has thermal performance of the following indicators:

(1) heat transfer coefficient (K): in the steady-state conditions, on either side of the enclosure air temperature difference of 1 ° c, the unit of time passing through 1m2 area. Unit: W/m2 ° c. It is the characterization of the thermal capacity of envelope delivery. K value smaller envelope, the lower the heat capacity, heatinsulation performance better.

(2) thermal inertia index (D): characterization of retaining structure on temperature Wave attenuation of fast and slow level of dimensionless index, its value is equal to the thermal resistance and thermal storage material layer coefficient multiplied. D = S×R, where s is the material heat conductivity W/m2K, R for material resistance m2K/W. D value, the greater the temperature Wave attenuation in the faster the envelope's thermal stability is better, better energy efficiency.

(3) shading coefficient (SC): actual through windshield heat gain of solar radiation and through 3mm transparent glass solar radiation heat gain ratio of. It is the characterization of window shading and translucent system performance of dimensionless index, the value in the range 0 to 1. SC, through the window transparent system of solar radiation to heat, its shading performance better.

(4) the window wall area ratio (W/W): Windows hole area and the ratio of the facade area. In General, the greater the window wall area ratio, the greater the energy consumption of buildings.

China's vast differences in climatic conditions around is very large, the country is divided into five areas of climate zones: the cold, cold regions, hot summer and cold winter, summer and warm winter area to moderate regions. Building energy-saving to different climate zones of the building envelope insulation requirements have different requirements.

Where: East three provinces and one city (Jiangsu, Zhejiang, Anhui, Shanghai), the majority were in hot summer and cold winter region (except North of huaiyin city, Jiangsu Province), under the public building energy-saving design standards ", the regional envelope heat transfer coefficient (K) requirements: roof ≤ 0.70; facades and the underside of an overhead or overhanging floor ≤ 1.0; exterior window (including transparent curtain wall, window and wall area ratio ≤ 0.7) ≤ 2.5 ~ 4.7; shading coefficientvalue ≤ 0.40 ~ 0.55.

Under the public building energy-saving design standards, indoor air conditioning system (General room) calculation parameters (mostly used as a basis for calculating the energy consumption basis) for the winter: 20 ℃; wind speed 0.10 ≤ v ≤ 0.20m/s; relative humidity 30%-65%. Summer: temperature 25 ° c; wind speed 0.15 ≤ v ≤ 0.30m/s; relative humidity: 40%-65%.

For building the data center, its room regional environmental temperature and humidity environmental requirements are based on equipment and room design standards, also is usually required in conformity with the public building energy-saving design standards, enhance data center room area for building thermal compound calculation and design of processing (mainly because of the basis for the calculation of temperature and enthalpy value point different).

Strict compliance and the implementation of the public building energy-saving design standards "and other countries of the standard specification for architectural design, is to ensure that the data centre building energy-saving requirements for the achievement of public basic approaches and measures. At the same time, according to the data center is located five climate zone of the external environment; data center is located in a building where the external environment in the region; and data center within the functional area of rooms adjacent to the layout of the internal environment, the key to IT equipment regional housing need to strengthen the measures that reasonably calculated thermal insulation, thermal parameters, select the appropriate envelope and materials.

Data Center construction and building thermal energy-saving way of relating to energy-saving measures primarily concerned with the support structure, interior wall insulation, insulation, six cube enclosure, heat treatment, no window bridgeAirtight sliding types, and other aspects.

For envelope use composite wall energy-saving technologies, the main structure in the wall adds one or several layers of composite insulating materials to improve the entire wall thermal performance. Composite wall energy technologies according to insulation in the walls of the position include: inner insulation, thermal insulation, combined in the thermal insulation and thermal insulation. In engineering practice, interior wall insulation is a data center, the most common form, mainly because of the addition of several insulation technology in architecture and structure of the previous design will determine when, having implemented simultaneously with the principal part of the project, except a few IDC or large enterprise data center architecture for the entire one; most data center just occupy public buildings in a local area, but also, most data center construction and civil engineering works, usually in the design of the synchronization is completed, the subject at a later stage (e.g. decoration engineering phase) before entering the design and construction. So in addition to the interior wall insulation technology, plus several insulation technology more difficult to achieve. Interior insulation wall usually efficient insulation between the main walls are combined, the construction process is relatively simple.

In the data center construction of engineering practice, the usual insulation are: mineral rock wool, polystyrene, polyurethane, gypsum board, etc. Choice of insulation heat transfer coefficient (K) a smaller value or thermal inertia index (D) the higher the value, the envelope of the lower heat capacity, its better thermal insulation performance, better energy efficiency.

Where possible, the use of heat transfer coefficient (K) the value of thermal insulation. On the roof, floor and walls of the six-party body for thermal insulation, to reduce the envelope around the heat transfer coefficient, the overall data center room regional packages to achieve better sealing and insulation energy saving effect.

As the building envelope, form a beam, Wale, seismic column of reinforced concrete, reinforced concrete shear walls, beams, columns, and other parts of the heat transfer coefficient is much larger than the main parts of the heat transfer coefficient, the formation of heat intensity channel for heat bridges. On the thermal bridge parts should be insulated to guarantee thermal bridge part of the inner surface temperature in the room air temperature and humidity conditions below the dew point temperature. Reduce the temperature difference between the sides of the envelope, eliminating thermal bridge effect, reducing the external physical environment on indoor environment of heat transfer, reducing thermal bridge part enclosure heat loss.

Current popular data center hosts housing area with no Windows sealed sliding types to avoid and reduce solar radiation into the rooms, as well as window or transparent curtain wall with heat, the temperature difference is lower air conditioning energy consumption means and measures. The original use of curtain wall with host room area should make full use of curtain wall panel behind the space, the use of efficient, durable insulation materials for insulation. Support for data centre districts and auxiliary rooms, Ribbon using window glass sliding types, should control building toward and window wall area ratio, the use of double-glazed or low-e glass (curtain walls), and assisted with sunshade installations (shading, solar etc.) to reduce the amount of solar radiation.
　　
5 air conditioning energy saving lighting means and measures

Data Center, covering the main object of building energy saving as air conditioning and lighting. Note: the supply and distribution system and key equipment of energy-saving IT as a special energy-saving technologies in electrical measures (this article does not discuss the extension).

In the data center, in order to meet the technological requirements in the datacenter, the air conditioning generally refers to the engine room project specific dedicated precision air-conditioning equipment.

Precision air conditioning equipment of primary energy saving and energy-saving measures: cooling load calculation, reasonable set parameter, the return of air supply mode, choosing high EER equipment, hot and cold air conditioning, a dynamic combination of operators, etc.

Accurate calculation of cooling load in a data center including: engine room equipment for cooling, building envelope of heat and solar radiation, the human body heat saturated, lighting equipment, thermal, fresh wind load, etc. Reasonably control data center area of refrigeration parameters (temperature and humidity settings). According to the report: refrigeration parameter variation 1 ° may produce 5% to 10% of energy consumption. Efficient design and layout of the return air supply and air supply and return air channel. Selection of refrigeration coefficient of performance (COP), energy efficiency ratio (EER) of air conditioning equipment, should be higher than in the public building energy-saving design standards of GB50189-2005 air conditioning equipment, as well as the computer and data processing engine room air conditioning with modular machine "GB19413-2003 require precision air-conditioning equipment minimum efficiency ratio indicators. Use of hot and cold air conditioning ventilation system. Due to a combination of air conditioning equipment, dynamically configured to improve the efficiency of refrigeration systems. On large data center room air-conditioning systems the use of refrigeration coefficient of performance (COP), energy efficiency ratio (EER) high water chillers and air conditioning systems, cold source using cold water.

Lighting system for major energy saving and energy-saving measures: follow the lighting power density limits, choosing energy-efficient appliances, lighting combination control, proper use of natural light.
>
In the public building energy-saving design standards "GB50189-2005 involving energy saving lighting system is based on the standards of architectural lighting design-2004 GB50034, the lighting design of the system should be strictly in accordance with the standards of architectural lighting design, data center room area and the associated region (illuminance and luminance uniformity) lighting metrics (e.g. host room 500lx) as well as the lighting load power density (LPD) values (15W/m2) for lighting design configuration. Choose efficient energy-saving lighting, lamps and accessories. For effective, flexible, combination of lighting control system. In the data center of the support zone and auxiliary rooms, and other functional areas appropriate use of natural light.

In addition, the existing data center computer room environment monitoring system for the environment and air conditioning equipment, electrical equipment, lighting equipment, such as display, record, control, alarm and trend analysis and tips feature dynamically monitor and control energy situation, with advanced technology and effective way to achieve data center energy consumption savingsPurposes.
　　
6 closing

Data Center due to its own characteristics, in a building is a "power users". In the public building energy-saving design standards "GB50189-2005 is to building envelope, heating ventilation air conditioning and lighting energy consumption for the three main aspects to consider the approach and building energy-saving measures. This article combines the standards relate construction energy conservation of three main areas, and to data center construction design for the pilot to improve a building's envelope insulation, etc. to improve thermal performance; heating, ventilating and air conditioning systems; improving lighting energy efficiency ratio of the target for energy saving equipment efficiency, data center architecture approaches and measures related to energy saving. In actual practice, a variety of reasons, in the data center's overall design links and building thermal cycles, on building energy conservation awareness and response a shortcoming, therefore, this article focuses on these two aspects were explored, expect to be able to have a public building energy efficiency, and data center energy saving special projects provide some recommendations and reference.