Thermal Balance & HVACR


In our daily work our customers often encounter problems like these:

  • Do I need more installed cooling power when operating additional equipment?
  • When it is warm outside, we don't have enough cooling, do I really need a new air conditioner?
  • Are my air conditioners (still) delivering their nominal cooling power?
  • How much waste heat is generated by my running equipment?
  • How much air moisture is there and how does it change with (seasonal) temperature changes?
  • How long does it take to reach temperature X when cooling / heating fails?
  • Do I need to do something now when there are more hot days coming?

We support you with these and similar questions, by helping you find the correct problem definition, clarifying definitions (thermal balance, dew point, ...), measuring relevant data (air temperature and moisture - also long term measurements, surface temperatures, air flow) and compute a thermal balance to create a clearly laid out view of key influences on the situation.

We also solve questions that are otherwise only accessible via rough estimations or even not at all using conventional approaches. For example we can calculate how long it will take until a certain temperature threshold is exceeded after breakdown of air conditioning. Our predictions are remarkably exact with deviations of only 0.2°C between calculation and actual measured values during an event. Using this information it is easy for example to come up with the best option for an emergency response contract with your HVACR supplier.

With our service you

  • Have solid, impartially measured data for your talks with your HVACR supplier.
  • Can decided on investments independent of a hardware supplier and without risk of getting the size wrong.
  • Tackle problems before they harm your business.
  • Answer questions that can only be roughly estimated using conventional approaches.


Our analytic process

Without setting up a complex simulation we first measure current temperature, moisture and flows. Depending on the problem we record static data (how efficient is the cooling unit?) or dynamic data (how long can the emergency cooling keep up?) and calculate the energy flow from that. This gives us information about how much heat is generated (for example through the operation of compressors, computer-racks and so on) and how and whereto is the heat removed from the system. Based on that we determine the necessary, respectively sensible size of the cooling or heating equipment. In this way we can give you fast, independent and konkrete advide: how to cover summer heat periods? Do we need additional coolen when we extend operations? What should reaction time should your emergency HVACR contract contain? How long can emergeny cooling be kept up?

For a number of notable customers - for example the Austrian National Bank (see CFD computing center cooling of the Austrian National Bank and the graph below) and the server room of the Austrian Environment Agency - we could answer these questions completely independent of enterprises that sell cooling units. Depending on the complexity of your situation, you will get our answer in just 1-2 weeks after the measurements. Your business and planning risks become controlled and can be estimated with high precision, energy costs decrease and you can re-negotiate your emergency cooling contracts on basis of concrete, independent measurements. Contact us! Summer is coming!

A first look at your particular situation is completely free in any case! Just send a message to office(at)rheologic.at!


Examples


T-Systems

Evaluation of saving potential for cooling power

T-Systems is a global player in ICT providing IT-infrastructure to many well known companies. In its datacenter in Vienna, Austria where HSG-Zander (global parent company: Bilfinger) is in charge of facility management, in cooperation with Schneider Electric energy savings potential was identified in existing server rooms by Rheologic.

After temperature and flow measurements in the server room actual cooling power of the CRAHs was calculated and an energy balance with fine granularity was created. Based on the measurements and the energy balance those parts of the server room where identified where optimisation is possible and feasible. Previously unquantified saving potentials for cooling energy and for CRAH efficiency were quantified and payback of retrofitting evaluated.

Finally a number of recommendations were given which improve the current cooling efficiency. The recommendations range from very simple measures (very simple retrofits, administrative changes) to complex changes of installations. We would like to thank Schneider Electric, HSG-Zander and T-Systems for the constructive and professional participation in the project.



OeNB (Austrian National Bank)

Simulation and implementation of emergency cooling operation
in a server room of OeNB

Task


Engineering of emergency operation in a separated server-room. One part is mostly free standing racks cooled by redundant CRAHs. The other part is housed racks using in-row cool loops. Correct ventilation layout in the separation wall between the two parts of the server room enables stable cooling for emergency operation. Ventilation starts automatically if the cool loops fail.

Simulation

In a virtual geometry the required flow rates for the fans in the separation wall was calculated to achieve a stable maximum end temperature in case the in-row cool loops fail to operate correctly.

Result

Application of CFD-Simulations for engineering of emergency cooling operations has shown to have many benefits compared to classic approaches:

  • Exact forecasts: exact planning of construction work
  • Retro-fit: costly constructions are minimized
  • Dynamic problems can be solved as well (eg. time to emergency temperature limit)
  • Payback of capital expenses is known in advance: minimal investment risks

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UBA (Austrian Environmental Agency)

Saved more than 30% of cooling power in the server room of the Umweltbundesamt (UBA)

Using only simple improvements (without any CAPEX) cooling power was reduced by 30%. Using current average electricity costs the yearly savings exceed 10.000 EUR.

Energy consumption for summer and winter in the graph are quite similar due to facility restrictions; it is not possible to control outside-in air flow.


OeNB (Austrian National Bank)

Cooling of Critical Hot-Spots in a Server Room of the Austrian National Bank

In cooperation with the IT-Operations department of Austrian National Bank (OeNB) critical parts of the infrastructure were measured and simulated to ensure reliable cooling and operation of the installed equipment. After implementation of the proposed measures no overheating of the critical components were observed.

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