Thermal energy storage (TES) involves adding heat (thermal) energy to a storage medium, and then removing it from that medium for use at some other time. This may involve storing thermal energy at high temperatures (heat storage) or at low temperatures (cool storage).
In HVAC applications, the most-common storage media used for cool thermal storage are ice and water. A chilled-water storage system uses the sensible-heat capacity of a large volume of water to store thermal energy. A chiller is used to lower the temperature of water, and this cool water is stored in a large tank for use at another time. An ice storage system, however, uses the latent capacity of water, associated with changing phase from a solid (ice) to a liquid (water), to store thermal energy.
已经引入了几种冰储存技术，在短时间内蓬勃发展，随后离开了市场。基于糖的冰储存系统仍然非常流行，因为它们很简单并且与传统的冷水系统相似。任何适合冷水系统的应用都是基于糖的冰储存的候选者。
This type of ice storage system uses a chiller to cool a heat-transfer fluid, often a mixture of water and antifreeze (such as glycol), to a temperature below the freezing point of water. This fluid is pumped through one or more ice storage tanks, where heat is transferred from the water inside the tank to the heat-transfer fluid. This causes the water inside the tank to freeze.
稍后需要热能时，再次将热量转移液再次通过储罐泵送，但现在处于水的冰点以上的温度下。热量从热转移的液体转移到储罐内储存的冰，从而导致冰融化。
将冰存储添加到HVAC系统中可以通过将冷却器的运行从高成本电力转移到低成本电力时来降低与冷却相关的实用性成本。
上图显示了示例建筑物的设计日冷却负载配置文件。在午夜至凌晨6点之间，建筑物没有占用，没有冷却负荷。凌晨6点，建筑物开始被占据，冷却负荷增加。冷却负荷在上午11点至下午4点之间最高，然后在人们离开建筑物时下午5点后大大减少。在整个晚上，在午夜离开之前，有一个小的冷却负荷。
大多数电力公司在白天的电力需求最大，甚至有些人面临短缺。为了鼓励在这段时间减少用电，许多电力公司已经建立了日期费率，在这些高需求期间为高成本电力创造了时间窗口。电力成本高的时间通常被称为“峰值”时期。另一方面，“非高峰期”时期是指较低的电量的时间。
对于同一示例建筑物，中午至晚上8点被定义为高峰期。所有其他小时都定义为非高峰期。
Another common component of the electric utility rate is a demand charge. This is a fee based on the highest power (kW) draw, or demand, used by the building during a specified time frame. Typically, either the demand charge only applies to the on-peak period, or the on-peak demand charge is significantly higher than the off-peak demand charge.
冰储存系统通过融化冰以满足在高峰时段的建筑冷却负载来降低每月公用事业成本。这避免了或大大减少在此时间范围内操作冷却器所需的电力。冷却器的运行转移到了非高峰期，在此期间，电力成本较低，需求充电较低或不存在。在此期间，使用冷水机将水冻结在储罐内部，将热能存储到峰值时期。
在此示例中，通过融化储存的冰，并关闭冷水机，可以满足峰值时期发生的建筑物冷却载荷。
这种类型的系统通常称为“全存储系统”，只有当储罐的存储容量足够大以满足给定一天的高峰冷却负载时，才有可能。
但是，全存储系统的安装成本可能是不可行的。许多冰储存系统具有足够的能力，只能满足一部分在峰值冷却载荷。这种类型的系统通常称为“部分存储系统”。
在此示例部分存储系统中，通过熔化冰和操作冷却器来满足在峰值期间发生的冷却载荷。冷却器以降低的容量运行，消耗更少的能量，并降低功率。通过融化储存的冰，可以满足冷却载荷大于冷却器提供的容量。
在峰值期间关闭冷却器，或大大降低其容量，可减少这种高价电力的消耗，并减少峰值电气需求。两者都可能导致较低的每月公用事业账单。
At first glance, it might appear that an ice storage system designed to reduce on-peak electrical demand (kW) is the same as a system designed to reduce on-peak electrical consumption (kWh). Which of the two is most important, however, can significantly change how the system is designed and/or controlled.
To reduce the on-peak demand, the system should melt ice only when the electrical demand of the building is highest. It is perfectly acceptable to have ice remaining inside the tank at the end of the day. This approach, called “peak shaving,” is commonly used when the on-peak electrical demand (kW) rate is high, but the electrical consumption (kWh) rates are nearly equal from off-peak to on-peak periods. Peak shaving attempts to find the optimum balance between reducing on-peak electrical demand (by melting ice and operating the chiller at reduced capacity) and avoiding significantly increasing off-peak electrical consumption (which happens when the chiller needs to operate in the ice-making mode).
Alternatively, to reduce on-peak electrical consumption, the system should melt as much ice as possible every day. This approach, called “load shifting,” is commonly used when the on-peak electrical consumption (kWh) rate is significantly higher than the off-peak consumption rate. Load shifting attempts to reduce on-peak electrical consumption as much as possible by melting all of the ice during the on-peak period, and shifting chiller operation to the off-peak period.
尽管设计用于峰值剃须的系统可能具有与用于负载变速的系统相同的冰存储容量，但这两个系统的控制方式不同。
除了降低每月的公用事业成本外，储冰的另一个潜在优势是降低机械冷却设备的尺寸和容量。
When ice storage is used to satisfy all or part of the design (or worst-case) cooling load, the chiller may be able to be downsized as long as the downsized chiller has sufficient time to re-freeze the water inside the tanks.
较小的电动冷却器也可能导致建筑物的电气服务较小，这也可以降低安装成本。
潜在好处
- 降低公用事业成本
- Lower on-peak electrical consumption (kWh)
- Lower on-peak electrical demand (kW)
- 设备尺寸更小
- 较小的冷却器
- Smaller electrical service (A)
- 降低安装成本
- 可能有资格获得公用事业折扣或其他激励措施
While the ice storage tanks add to the installed cost of the system, the impact of downsizing the mechanical cooling equipment may offset some (or all) of this added cost. Additionally, some electric utility companies offer rebates or other incentives when ice storage is used to reduce on-peak electrical demand. When these incentives are available, adding ice storage may even reduce the overall installed cost of the system.
在某些装置中，可以实现这些好处。但是，在其他装置中，可能不会发生一个或多个。例如，添加冰存储可能会降低公用事业成本，但是将水箱内的水重新冻结的时间可能很短，以至于冷却器必须保持相同的尺寸，以便足够快地冷冻水。
参考
TRC019-EN冰存储系统
下载参考
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