Physical separation in DC

Being an expert in the field of DC operation, WCooliT conducts an integrated DC survey on Customer’s request, helps to identify and analyze all sources of losses and probable steps towards their minimization. The resulting report allows to conduct detailed works on elimination of power losses and finally increase energy efficiency of DC.

Taking the responsibility for performed surveys, WCooliT ensures (along with signing legally binding documents) the achieving of specified characteristics in the report.

It is difficult to overestimate the importance of measures, such as physical separation of cold and warm air. This must be the most effective solution if to compare measures of physical separation with an effect that could be achieved. We should first evaluate the cost of losses:

A little bit of math:

  • output capacity:

QkW= Lm3/s·ΔTK°·ρkg/m3·CkJ/K°·kg

Lm3/s = Sm2·Vm/s


  • open unit:
S(1U) = K 19”·1U = 0,483·0,045 = 0,022 m2
Q(1U)  = 0,087·12·1,2·1 = 1,252 kW

If to transfer these figures into the money we shall obtain:


  • Cooling:

Q(1U)  = 0,087·12·1,2·1 = 1,252 kW

  • Underused investments:

1 500-00 USD for 1 kW of cooling;

1 500-00 USD x 1,252 kW = 1 878-00 USD “fall out” into an open unit;

1 878-00 USD x 48 U = 90 000-00 USD “falls out” into an open rack.


Q(1U)  = 0,087·12·1,2·1 = 1,252 kW

  • Not received income:

Rack of 6 kW IT-Load brings 2 667-00 USD/month;

1.252 kW in a rack brings: 2 667-00 / 6 · 1.252 = 557-00 USD/month;

557-00 USD/month = 6 680-00 USD/year;

Losses in case of one open unit – 6 680-00 USD in a year!

Losses in case of an unclosed rack – 333 000-00 USD in a year!

Additional costs:

Q(1U) = 0,087·12·1,2·1 = 1,252 kW

No use – no consumption? – PUE!

  • additional costs for electricity:

0,13 USD/kWh

1.252 · 0,13 = 0,17 USD/hour

0,17 USD · 24 = 4-00 USD/day

4-00 USD/day · 365 days/year = 1 460-00 USD/year

As we see from calculations, without physical air separation DC as an enterprise not only looses investments and bears direct losses, but also doesn’t receive the revenue it could have received.

By applying a number of measures aimed at reduction of nonproductive power losses, it is possible to increase economic efficiency of DCs.

At the same time if to undertake a number of additional studies and calculations, in most cases it is possible to increase an average power density for one rack from 4-5 kW up to 7-8 kW for one rack.

What you need to use for the organization of the physical separation of the air flow can be found here