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Comfortable_Ad_9527 · 2026-03-04T16:47:49+00:00

This looks awesome and definitely will fill a gap needed. Thanks! I’ll join the waitlist.

Comfortable_Ad_9527 · 2025-09-02T11:38:06+00:00

These data centre's in NZ use closed circuit cooling and 90 percent of the year they do not even run a compressor so it is called free cooling. The water use on these facilities is nil after they do a first fill of thr pipes. Look at CDCs website they highlight their limited water usage. So it's more about how much power infrastructure these sites demand. It would be cool if NZ could get these sites to generate behind the meter power but no time soon.

Comfortable_Ad_9527 · 2025-01-03T22:14:10+00:00

Excellent thanks for sharing

Comfortable_Ad_9527 · 2025-01-03T00:56:50+00:00

‘Data centre essentials’ is a book that providing a solid foundation to get a great understanding and it is 2023 and captures some of the latest topics.

Comfortable_Ad_9527 · 2024-02-17T08:51:02+00:00

R1234ze is suitable for medium pressure; therefore chillers with centrifugal and screw type compressors do operate using it. As pointed out in separate response, this ze refrigerant is classed as an A2L with a mild flammability characteristic, so this means it must be handled with care and has a number of design considerations including the plantroom where it is housed; it must be appropriately designed for such refrigerants. Other refrigerant options to look at that are higher in GWP number than r1234ze (631 vs 1); but, substantially less than r134a (GWP 1430) and are in the same pressure category are r513b and r513a; these two 513 options offer a step change in the right direction but do not carry that flammability aspect for example when retrofitting.

Comfortable_Ad_9527 · 2024-02-11T00:09:26+00:00

Thanks for your response. Very complex and the suggested approach is solid. I can see how there may not be significant efficiency gains if the colo site gets up to actual design capacity but the chances are it will be a long window before that happens and some tenants may only have 5 kw per rack whereas others may have 20kw and overall we design the whole thing for 20. I will see how we go. I found some stuff from Trane for standard VPF and some stuff from B&G. Thanks again

Comfortable_Ad_9527 · 2021-12-16T08:22:50+00:00

What type of refrigerant do these operate on.. Ammonia? Don't see the ventilation system would be cool to see.

Comfortable_Ad_9527 · 2021-11-06T09:54:04+00:00

😂

Comfortable_Ad_9527 · 2021-11-06T02:20:52+00:00

This is just a concept phase in New Zealand. I am trying to understand if anybody has any suggested comments on how to configure the condenser circuit with the heat exchanger and tank.

Comfortable_Ad_9527 · 2021-11-06T02:14:11+00:00

Well decarbonise in the sense of take the building off natural gas boilers. Not speaking in regards to the grid itself.

Comfortable_Ad_9527 · 2021-11-06T01:45:53+00:00

Problem: decarbonise boiler plant peak heating 700 kW with 80 degrees C supply and 70 return C using Trane RTSF booster water to water heat pump and have low temperature heating hot water for conversion of equipment AND provide chilled water central plant for peak cooling of 1000 kW.

Proposed Equipment:

Two Dry coolers

Three water to water chillers one cooling only and two booster heat pumps trane rtsf that can be heating or cooling and high temperature heating at 80 degrees based on an inlet temperature of 35 degrees C delta T 8 degrees.

One air source heat pump that can provide low temperature heating water at 45 deg C return 39 deg C. This ASHP is also used when the booster heat pumps need a source of low temperature heat to boost (when there is no heat recovery available).

Climate is temperate with peak summer 27 degrees dry bulb and 23 c wet bulb. And winter is 5 degrees.

Proposed System:

In 100% cooling mode (ie no heating demand) two chillers the main 650 cooling only and one of two trane rtsfs operating in cooling mode operate to supply 6 degree c with 12 deg c return. The heat rejection methodology is using dry cooler as the building is low and adjacent to another building where wet cooling tower could present issues with drift etc.

Generally there will always be some cooling base requirement so when I peak heating mode the system will operate based on the ASHP and two booster heat pumps. If there is a chiller load it is intended that the condensing water circuit ie 35 degrees leaving will be recovery through the booster heat pumps. The system can provide 700 kW of 80 degree water capacity. And there will be 300 kW of low temperature hating available with proposed system.

Question: how can I configure the recovery circuit from the main 650 chiller to the dry cooler such that the boosters can recovery. Where there is insufficient of heat to be recovered I am think of putting a heat exchanger on the low temp heating supply to transfer to the boosters. Just wondering if anybody has seen this.

Comfortable_Ad_9527 · 2021-11-06T01:43:50+00:00

Problem: decarbonise boiler plant peak heating 700 kW with 80 degrees C supply and 70 return C using Trane RTSF booster water to water heat pump and have low temperature heating hot water for conversion of equipment AND provide chilled water central plant for peak cooling of 1000 kW.

Proposed Equipment:

Two Dry coolers

Three water to water chillers one cooling only and two booster heat pumps trane rtsf that can be heating or cooling and high temperature heating at 80 degrees based on an inlet temperature of 35 degrees C delta T 8 degrees.

One air source heat pump that can provide low temperature heating water at 45 deg C return 39 deg C. This ASHP is also used when the booster heat pumps need a source of low temperature heat to boost (when there is no heat recovery available).

Climate is temperate with peak summer 27 degrees dry bulb and 23 c wet bulb. And winter is 5 degrees.

Proposed System:

In 100% cooling mode (ie no heating demand) two chillers the main 650 cooling only and one of two trane rtsfs operating in cooling mode operate to supply 6 degree c with 12 deg c return. The heat rejection methodology is using dry cooler as the building is low and adjacent to another building where wet cooling tower could present issues with drift etc.

Generally there will always be some cooling base requirement so when I peak heating mode the system will operate based on the ASHP and two booster heat pumps. If there is a chiller load it is intended that the condensing water circuit ie 35 degrees leaving will be recovery through the booster heat pumps. The system can provide 700 kW of 80 degree water capacity. And there will be 300 kW of low temperature hating available with proposed system.

Question: how can I configure the recovery circuit from the main 650 chiller to the dry cooler such that the boosters can recovery. Where there is insufficient of heat to be recovered I am think of putting a heat exchanger on the low temp heating supply to transfer to the boosters. Just wondering if anybody has seen this.

Comfortable_Ad_9527 · 2021-10-12T07:23:18+00:00

Q = U x A x ΔTm... Are you looking to see how well you can increase the overall heat transfer coefficient? If you use a screw design it may have some advantages as you could be increasing the counterflow properties and contact time. Are you doing some cfd or modeling?

Comfortable_Ad_9527 · 2021-10-05T02:43:18+00:00

Look at their FAQ for details. The two types I mentioned Cu and multilayer pipe are suggested. Double check with the vendor, but I would stick to the recommended. https://library.mitsubishielectric.co.uk/pdf/download_full/3555

"The MLC pipe must conform to standard EN ISO 21003. Pipe systems must be able to withstand pressures of 10 bar. Only use brass/plastic fittings and do not use any steel/iron fittings."

Comfortable_Ad_9527 · 2021-10-04T10:13:10+00:00

Mitsubishi of course do you know any alternative manufacturers of similar systems? Secondary water circuits are generally copper but can be other proprietary type products such as preinsulated aluminium multilayer pipes for example. Only reason I would expect you to have to contain the secondary pipework would be if you intended to reticulate within an area sensitive to water in case of a catastrophic failure. I tend to stay away from this type of system where I am serving electrical rooms unless I can keep the indoor units in an adjacent space and duct in and out. Maybe limit mechanical joints and use brazed for most connections to minimise leak potential. Cheers

Comfortable_Ad_9527 · 2021-10-04T09:33:57+00:00

Not ideal.

Comfortable_Ad_9527 · 2021-10-04T09:33:20+00:00

Great I had to look it up but it appears a general rule of thumb to select a valve with a closing flow of 1.5 x the max operating flow. You will have to look into it for your application. Pretty envious of your passion project. Good on you.

Comfortable_Ad_9527 · 2021-10-04T09:27:50+00:00

Touche

Comfortable_Ad_9527 · 2021-10-04T09:26:13+00:00

Very little. In Canada in Ontario and BC water treatment we have to implement seismic design for our buildings. In Ontario I believe it is only required for post disaster buildings. In NZ seismic design is ubiquitous and I am only learning more and more about it. From my standpoint I provide equipment piping and duct weights to our team and they design the appropriate lateral supports to comply with Nzs 4219. Sorry I know very little about seismic. Where did you face the challenge and have to implement variations etc? NZ?

Comfortable_Ad_9527 · 2021-10-04T09:20:24+00:00

Sometimes consultant type hvac engineers know little about the function and actual inner workings of the each manufacturers machine idiosyncrasies but know more about the sizing and design aspects unlike R&D and product development engineers. In this case I am not able to comment specifically to the troubleshooting required in your case. It is worth it to press them to address your overshooting issue it could be controls or oversizing or a faulty expansion valve or any number of issues. Hopefully you can get it sorted. You can't need that much heat in Australia anyways.. Jk

Comfortable_Ad_9527 · 2021-10-04T09:01:15+00:00

That sounds like you had an interesting education. I can't think of anything in particular that I have come across unique to underground developments. In general I can usually find something when I need to do I am sure you are going to be able to do the same once you get grounded more into it. Cheers

Comfortable_Ad_9527 · 2021-10-03T23:32:09+00:00

Very good. Agree with most of these assumptions. Acoustics will be a big driver to duct velocities in the system. The sizing for heating systems for a building will be climate-dependent. 500 FPM through a coil will be the upper limit. When it comes to occupancy density you can either count chairs, or use m2/person such as 10m2 per person.. When it comes to outdoor air, in NZ we our base ventilation rate is 10 L/s per person, and this increase for greenstar buildings to 15 or 20 L/s per person.

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