Liebert XD systems
July 16, 2010 at 9:28 am | No comment | Category: IT Cooling Systems
The Liebert XD system offers a flexible, energy-efficient solution to your extreme density cooling needs. By eliminating the extreme heat densities associated with increased computing capacities, the Liebert XD system enables IT and data center managers to take advantage of the newest, most advanced computing technologies available– which means your computing and cooling can keep pace with your business.
What is the Liebert XD system?
Liebert XD is a high heat density cooling solution that offers solutions utilizing Open or Closed Architecture, Water based or Pumped Refrigerant based technology, and a wide range of equipment configurations. Open architecture systems utilize cooling coils near the heat load, either inside or outside the open server rack, and utilize the room air volume as a thermal storage to ride through short power outages. Closed architecture systems fully enclose the rack with the cooling coils inside. Other provisions are required for power-loss ride-through. Pumped Refrigerant technology eliminates the presence of water in a data center. It operates at low pressure in the piping system and becomes a gas at room temperatures, if a leak would occur. It utilizes micro-channel coil efficiency and low pressure drop.
Water based systems offer a cooling alternative where electrical hazards are minimal or the use of water is not a concern. They are also designed to work in any size space from a small computer room to a large data center.
How can I design a Liebert XD high heat density cooling solution with built in redundancy?
Redundancy can be designed into a solution utilizing the open architecture version of Liebert XD by combining CRAC units and interlaced pipe connection between the cooling modules and the supporting XDP/XDC. The interlaced connection means that cooling modules next to each other are connected to different XDP/XDC units. For the XDH, which has dual piping circuits, this interlacing can even be done within each module.
How much time do I have until the servers start to shut down in case of a cooling system failure?
For a closed architecture cooling solution, how fast this situation might occur depends in general on the load in the rack, the thermal mass in the rack and the heat exchange with the surroundings (leaks). In extreme situations, an over temperature situation can occur within seconds. For an open architecture solution, similar factors have an impact on how fast this situation would occur. However, since the room works as a heat sink, it will typically take minutes until an over temperature is reached. Full scale tests that Liebert have done together with Hewlett Packard showed that 104ºF entering air temperature to the server (which is the temperature when most servers start to shut down) was reached after 23 minutes at 3.5kW per rack heat load in the room. At 7kW per rack heat load, it was reached after 7 minutes; and at 11kW per rack, 104ºF was reached after 2 minutes.
What is the difference between Open and Closed architecture and which architecture is recommended?
Each architecture has its advantages. In general, an Open architecture allows the room to be a heat sink (for ride through during failures or power loss), does not limit the rack selection, has a less complex emergency mode and allows the racks to “borrow” cold air from each other. A Closed architecture solution has low audible noise, is deployable as a single rack, minimizes the air circulation in the room and does not require hot/cold aisle arrangement.
Why is Liebert XD called Supplemental High Heat Density Cooling?
The Liebert XD system is doing sensible cooling (the temperature of the cooling fluid supplied to the cooling modules is always above the actual dew point in the room so no condensation can occur on the coils in the modules or on the piping) to match the high heat density load. It supplements the precision cooling equipment which typically still is required for humidity control and air filtration.
State plans new clunker appliance program for central AC units
July 16, 2010 at 9:10 am | No comment | Category: Air Conditioning
June 30, 2010 | By Diane C. Lade, Sun Sentinel
Florida’s wildly popular Cash for Clunker Appliances program soon will be reborn with a new twist: Rebates for clunker air conditioning systems. State officials have approved a program that will give Floridians a flat fee rebate — the amount yet to be determined — for new Energy Star-rated central air conditioning and air source heat pumps systems purchased before the end of the year, said Brenda Buchan, the chief analyst with the Governor’s Energy Office who managed the Energy Star appliance rebate program.
Window or room air conditioning units will not be included, as these products were covered under the cash for appliance program. Buchan said Florida also is considering including Energy Star hot water heaters in the new program but a decision has not yet been reached. Only residential home installations will be covered. An added bonus: The state rebate, which will be funded with federal energy stimulus money allocated to Florida, can be combined with the federal energy tax credit available to those who purchase central air conditioning systems.
How to Make Your Air Conditioner More Efficient
May 26, 2010 at 6:30 pm | No comment | Category: Air Conditioning
In times of rising energy costs and rapidly depleting fossil fuels, making your South Florida air conditioner more efficient will reduce your energy usage, make your home more comfortable, save money, and possibly help to save the environment. No matter what kind of air conditioning system you have, there are steps you can take to make your air conditioning system more efficient without purchasing a new system.
Here are some basic tips on how to make your air conditioner more efficient:
- Have your air conditioner professionally serviced annually
- Clean your air ducts
- Install clean air filters every 3 months during the cooling season
- Find and seal all cracks in your house. Small cracks are not uncommon around seams, corners and other areas. These can be sealed with caulk.
- Find and seal any gaps or cracks around windows and doors. This can be accomplished with weatherizing tape or with caulk.
- Close the flue in your fireplace chimney. A surprising amount of air exchange can occur through an open flue.
- Use high-efficiency windows and doors or storm windows and doors. Well-insulated windows can reduce your cooling cost by 25-50%.
- Add weather-stripping to windows and doors to create a tight seal. If you are not planning to upgrade your windows and you want to achieve better efficiency, the same weather-stripping used in winter can be used to seal and insulate these areas.
- Use major appliances during the coolest part of the day or evening. Appliances generate heat when they are in use, particularly dishwashers, washing machines and dryers. Using these appliances during the cooler parts of the day causes less stress on the working of your air conditioner.
- Use shades and blinds to block the heat and UV rays from the sun. Shades and blinds provide more than privacy – they also deflect heat from the sun and the UV rays that could damage your furniture and carpeting.
- Add UV coatings or films to exterior windows. Many newer windows have low-e coatings which allow light to enter the room but block the heat and the UV rays. These coatings can be added to the windows by professionals or you can buy and apply sheets of UV deflecting film.
- Check the insulation around windows and doors. These are the greatest opportunities for gaps and cracks that allow heat exchange.
- Check the insulation in your attic (most heat exchange occurs through the roof). Be sure you have the right kind and amount of insulation and that your attic is properly vented.
- Use ceiling fans to better circulate the cooled air
- Use register/vent booster fans to better circulate the cooled air
- Seal off any unused/unconditioned parts of the house so cooled air will not escape into these areas and heat will not enter the main part of the house
- Use ventilation fans to carry heat and steam from the bathrooms and kitchen
These steps will make any air conditioning system more efficient. This will enable you to save energy and cost and reduce the demand on fossil fuels.
