When I first heard about Deep Lake Water Cooling I was shocked and amazed how great idea that was. I remember saying to myself “That’s genius!” cold water straight from the lake into the buildings no more need of those massive and noisy chillers. Right? Well, not so fast. After working in three buildings that use deep lake water cooling my opinion has changed a bit about the fantastic idea.

Everyone needs to admit! It’s a great idea no doubt, it has a huge selling point in this age of “green energy” and carbon emissions. Who doesn’t want greener energy in their buildings? Reduce Hydro and the carbon footprint at the same time? We all want that. The question is who is willing to pay the money for it?

The vision of deep lake water cooling is great, the reality not so much. From the energy efficiency stand point, one might say “but I don’t need to have chillers in my building anymore” that might be a plus, but I was sad to learn that the DLWC provider has many chillers (and boilers for their steam) to supplement the demand that the lake itself can’t handle.

My point is not to trash any provider, rather, my point is to share that even some great ideas come with high price tag and challenges attached to them.

When a sales person tells you, “this is green energy, this is affordable, this is maintenance free, this is the future” everyone wants to be part of that. In reality, as I mentioned, it’s not that green, the price is HUGE, super expensive (I won’t even mention the capacity charge that’s ridiculous), it’s not maintenance free because you have to maintain the heat exchangers, the pumps, the control valves and so on.

The other issue I have is how reliable the DLWC really is, a lot people tell me it’s super reliable. I have so far two major issues with DLWC none of them caused directly but the supplier, but they could be avoided. One floor was under construction in my building and the contractor balancing that floor, decided to open the main valve for the chilled water to that floor (in order to balance it) and that cause a major issue in the loop and we start sending water too cold back to the provider, the way the system is programed, when that happens the provider return valve starts to close in order to the loop pick up more heat before sending water back to them. At the particular day, we were sending 12 degrees C back instead of the 15 degrees C as per contract. The valve closed, we lost flow and that caused 3 major data centers to crash with temperatures getting to 39 degrees C in minutes. Many blade servers were damaged and the landlord had to pay over 80k to the tenants. How reliable is that again?

After that, to me particularly, the perfect scenario is a combination of both. If you can afford to have both systems that would be ideal. DLWC, so you can showcase that to your tenants and brag how green your building is. You can stop using cooling towers and reject that heat to a heat exchanger connect to the DLWC and save some water too. All that looks great on paper, but what really makes me sleep at night is knowing that at my site we have four big ass chillers there, whenever we want we can switch to DLWC but that is an option not a sentence.



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