Latest / NOXTalks / Ice Thermal Energy Storage: Can It Beat Your Demand Charges?

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Ice Thermal Energy Storage: Can It Beat Your Demand Charges? · NOXTalks

• 0:07
  SPEAKER_00: Welcome to Knox Talks, the AI-generated podcast exploring the groundbreaking ways technology shapes our built environment.
• 0:14
  SPEAKER_00: Today we're diving into the ice battery in the basement and whether storing cooling can actually beat your demand charges.
• 0:20
  SPEAKER_00: Picture this.
• 0:22
  SPEAKER_00: Four floors below a Manhattan Art Deco Tower begun in 1932, a building called Eleven Madison, 64 tanks quietly freeze water overnight.
• 0:33
  SPEAKER_00: By morning there can be more than half a million pounds of ice down there.
• 0:36
  SPEAKER_00: Then when the afternoon heat hits and the grid starts to sweat, the building melts that ice to cool its tenants instead of leaning on its chillers at the priciest hour.
• 0:46
  SPEAKER_00: That's thermal energy storage, or TES.
• 0:49
  SPEAKER_00: And well, it isn't new.
• 0:51
  SPEAKER_00: CalMac has been putting ice storage into commercial buildings since 1979.
• 0:56
  SPEAKER_00: So why talk about it now?
• 0:58
  SPEAKER_00: Because in more markets, the value of shifting electricity away from expensive peak periods is becoming harder to ignore.
• 1:05
  SPEAKER_00: Grids are straining under electrification, data centers, and cooling demand.
• 1:10
  SPEAKER_00: And old ideas having a genuine comeback.
• 1:13
  SPEAKER_00: When people hear demand response, they often think about shedding load when the utility calls.
• 1:18
  SPEAKER_00: Thermal storage takes a different approach.
• 1:20
  SPEAKER_00: Instead of simply curtailing demand, it shifts that demand to another part of the day.
• 1:25
  SPEAKER_00: The building doesn't go without cooling, it just makes that cooling earlier, when power is cheap, and banks it.
• 1:32
  SPEAKER_00: Here's why that matters.
• 1:34
  SPEAKER_00: In a lot of commercial buildings, cooling can be one of the biggest contributors to summer peak electrical demand.
• 1:40
  SPEAKER_00: So an ice tank is basically a battery aimed squarely at one of your largest loads.
• 1:45
  SPEAKER_00: The U.S.
• 1:45
  SPEAKER_00: Department of Energy's Better Buildings primer on thermal storage puts it plainly.
• 1:50
  SPEAKER_00: TES can lower peak demand, shift load, ease stress on the grid, and make heating and cooling more resilient.
• 1:58
  SPEAKER_00: It even notes that storage can let equipment be sized closer to average loads rather than peak loads.
• 2:04
  SPEAKER_00: Fun fact: Goldman Sachs's Manhattan headquarters has 92 ice tanks tucked beneath its trading floors.
• 2:11
  SPEAKER_00: CalMack once worked out that's enough ice for about 3.4 million margaritas.
• 2:17
  SPEAKER_00: So what about savings?
• 2:19
  SPEAKER_00: Ice Energy says customers in its Southern California virtual power plant have saved up to 20% on utility bills through load shifting.
• 2:27
  SPEAKER_00: And at 11 Madison, Train reports a 1,035 kilowatt reduction in summer peak demand, 25% lower central plant electricity consumption, and more than$730,000 a year in energy and operating cost savings.
• 2:43
  SPEAKER_00: Those are impressive numbers, but they're project specific.
• 2:47
  SPEAKER_00: The economics still come down to the building, the tariff, and how intelligently the storage is controlled.
• 2:53
  SPEAKER_00: There's also an honest trade-off, worth naming.
• 2:56
  SPEAKER_00: Making ice means running chillers colder, which usually costs you some efficiency.
• 3:02
  SPEAKER_00: Cooler night air claws a bit of that back.
• 3:04
  SPEAKER_00: So the guaranteed objective is usually lower peak kilowatts and lower cost, not necessarily lower total kilowatt hours.
• 3:12
  SPEAKER_00: And here's the part that gets overlooked.
• 3:14
  SPEAKER_00: The tank is simple, the brains are everything.
• 3:18
  SPEAKER_00: A field study of an ice storage system in a Chinese commercial building found real-world performance was far poorer than expected.
• 3:25
  SPEAKER_00: Too little ice in peak season, too much in the shoulder months.
• 3:30
  SPEAKER_00: Earlier research by Dries and Braun found that a simple chiller priority strategy could cost as much as 20% more than optimal control.
• 3:38
  SPEAKER_00: A 2022 Tsinghua University study paired day-a-head cooling load forecasting with optimized control at a Beijing complex, an 85,000 square meter mall, and a 56,000 square meter office building, sharing one cooling plant and a 76,000 kilowatt hour ice tank.
• 3:58
  SPEAKER_00: Their prediction-based strategy cut energy costs by 9.9%.
• 4:03
  SPEAKER_00: The point?
• 4:04
  SPEAKER_00: Knowing tomorrow's load helps you decide tonight how much ice to make.
• 4:08
  SPEAKER_00: The toolkit's growing too.
• 4:10
  SPEAKER_00: Beyond classic ice and chilled water tanks, researchers at Texas AM are working on salt hydrate phase change materials, chasing a system that could last 30 years.
• 4:21
  SPEAKER_00: Tie it into the BAS, add the telemetry and dispatch controls required by the grid program, and aggregated storage can even become a resource in a virtual power plant.
• 4:31
  SPEAKER_00: So where to start?
• 4:32
  SPEAKER_00: Three moves.
• 4:34
  SPEAKER_00: First, pull your utility bill and split out the demand charges from the time of use energy charges.
• 4:40
  SPEAKER_00: That's where TES pays back.
• 4:42
  SPEAKER_00: If demand charges are a small slice, storage probably won't pencil out.
• 4:46
  SPEAKER_00: Second, if there's a central chiller plant, ask whether storage can be added without oversizing everything else.
• 4:53
  SPEAKER_00: Done well, it can mean a smaller chiller, not a bigger one.
• 4:57
  SPEAKER_00: Third, make sure the charge and discharge decision is driven intelligently against your rate schedule.
• 5:03
  SPEAKER_00: Weather, occupancy, tomorrow's forecast.
• 5:07
  SPEAKER_00: Not run on a fixed timer that melts the whole tank by 11 in the morning.
• 5:11
  SPEAKER_00: Because the cheapest kilowatt at four in the afternoon is the one you're building quietly made at two in the morning.