with a focus on energy management in green data centers, rutgers university in new jersey builds a ground-breaking solar-powered data center ”parasol” with dantherm free cooling & air conditioning systems. 

rutgers university, the state university of new jersey, usa built their own ”green” data center named parasol as a research platform to improve the efficiency of data centers.  it is comprised of a small container, a set of solar panels and batteries.  the container is mounted on a steel structure placed on the roof of one of the university buildings. the solar panels are mounted on top of the steel structure and shade the container from the sun.  the container hosts two racks of energy-efficient servers (up to 160 servers) and networking equipment.  besides the solar panels, parasol can draw energy from its batteries and/or the electrical grid.  three manual switches enable different configurations for the supply of energy.  parasol also includes an extensive power monitoring infrsatructire to quantify how much energy is drawn from each avaiable source [1].

with the focus on energy efficiency, rutgers needed to partner with a thermal management provider equally focused on energy efficiency. dantherm was chosen because of their focus on energy efficient solutions for the telecom industry. a dantherm flexibox 450 free cooling system and a 19,000 btu/hr. air conditioner were selected. parasol uses the flexibox free cooling unit to control the temperature inside the container when the external temperature is lower than 84°f (29°c). the flexibox unit consumes 110w at half speed and maximum of 450w (230vac). when the temperature is higher than the free cooling threshold, the air conditioner starts working. the container uses free cooling whenever possible, and active air conditioning only as needed [1].

flexibox free cooling by dantherm, in short, is intelligently controlled ventilation.  the flexibox free cooling system works by introducing cool outside air low into the shelter and removing heat through a motorized exhaust damper mounted as high as possible on the opposite wall.   the flexibox free cooling system can be used as the sole cooling solution or in combination with an air conditioning system, prolonging the service life of the air conditioner significantly.  when ambient conditions are too hot for free cooling, the controller will shut down the flexibox and turn on the air conditioner.  the flexibox free cooling system is an extremely energy efficient total heat management system, with the ability to control external air conditioning units, a heater, and motorized damper. 

examples of air movement in a typical shelter

the parasol data center has been operating for 22 months.  when asked about the cooling behavior of the dantherm equipment, rutgers professor and co-leader of the paraol project thu d. nguyen commented ”we have found the combination of free cooling and air conditioning to be energy efficient.  we have observed that in our new jersey location, the air conditioning unit typically runs for no more than 20 days per year.  most of the time, free-cooling is sufficient to keep parasol cool.  we have measured an average pue (power usage effectiveness) of lower than 1.13, including power losses.  thus, we have been quite happy with the dantherm cooling systems.”  the u.s. department of energy now mandates a 1.4 pue for federal data center energy efficiency, so the energy efficiency results achieved at parasol are considered a success. 

www.dantherm.com   
http://parasol.cs.rutgers.edu

references

[1] parasol: a solar-powered µdatacenter, 2012. http://www.cs.rutgers.edu/~ricardob/papers/parasol.pdf.