Ice storage air conditioning

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Ice Storage Charger is the process of using ice for the storage of thermal energy. This is practical because of the high heat of water fusion: one metric ton of water (one cubic meter) can store 334 megajoules (MJ) (317,000 BTU) of energy, equivalent to 93 kWh (26.4 ton-hours).

Ice was originally obtained from the mountain or cut from the frozen lake and transported to the city for use as a cooler. The original definition of "tons of cooling capacity" (heat flow) is the heat required to melt a ton of ice over a 24-hour period. This heat flow is what is expected in a 3,000 square foot (280 feet) home in Boston in the summer. This definition has since been replaced by less ancient units: a tonne of HVAC capacity equals 12,000 BTU per hour. A small storage facility can accommodate enough ice to cool large buildings from one day to a week, whether the ice is produced by anhydrous ammonia chillers or transported by horse-drawn carts.

Ground freezing can also be utilized; this can be done in the form of ice where the soil is saturated. The system will also work with pure rock. Wherever ice is formed, the fusion heat of ice formation is not used, because the ice remains solid during the process. Methods based on soil freezing are widely used for mining and tunneling to strengthen unstable soils during excavation. Frozen soil uses drill holes with concentric pipes that carry saltwater from the chiller on the surface. Cold is extracted in the same way using saltwater and is used in the same way as conventional ice storage, usually by saltwater heat exchanger into liquids, to bring the working temperature to a level that can be used at higher volumes. Frozen soils can remain cold for months or longer, allowing cold storage for long periods of time with negligible structure costs.

Replacing existing air conditioning systems with ice storage offers a cost-effective energy storage method, enabling excess wind energy and other intermittent energy sources to be stored for use in the cold later, perhaps months later.

Video Ice storage air conditioning

Air Conditioning

The most widely used form of this technology can be found in air conditioners or air conditioning systems in large buildings on campus. Air-conditioning systems, especially in commercial buildings, are the biggest contributors to peak electrical loads seen on summer days in various countries. In this app, a standard chiller runs at night to produce a pile of ice. The water then circulates through the pile during the day to produce cold water which is usually the chiller's daytime output.

Partial storage systems minimize capital investment by running a chiller almost 24 hours a day. At night, they produce ice for storage and during the day they cool the water for the air conditioning system. Water that circulates through melting ice increases their production. Such systems typically run in ice-making mode for 16 to 18 hours a day and in ice-melting mode for six hours a day. Capital expenditures are minimized because the coolant can be only 40 - 50% of the size required for conventional design. Adequate ice storage to save half a day of rejected heat is usually enough.

The full storage system minimizes the energy cost of running the system by completely shutting down the cooler during peak load hours. Capital costs are higher, since such systems require a slightly larger refrigerant than partial storage systems, and larger ice storage systems. Ice storage systems are cheap enough so that full storage systems often compete with conventional air-conditioning designs.

The efficiency of an air conditioner cooler is measured by a performance coefficient (COP). In theory, thermal storage systems can make chillers more efficient because heat is thrown into colder night air than warmer daytime air. In practice, heat loss beats this advantage, because it melts the ice.

Storage of air conditioners has proved beneficial in the community. The fuel used at night to generate electricity is a domestic resource in most countries, so less import fuel is used. Also, research shows that this process significantly reduces emissions associated with producing power for air conditioning, because at night, inefficient "peaker" plants are replaced by low emission base load facilities. Plants that produce this power often work more efficiently than gas turbines that provide peak power during the day. In addition, because the load factor on plants is higher, fewer plants are needed to serve the load.

A new twist on this technology uses ice as a condensing medium for refrigerants. In this case, the regular refrigerant is pumped to the coil where it is used. Rather than requiring the compressor to turn it back into a liquid, however, low-temperature ice is used to cool the refrigerant back into the liquid. This type of system allows existing HVAC-based refrigeration equipment to be converted into Thermal Energy Storage systems, something that previously could not be easily done with cold water technology. In addition, unlike cold water-cooled water systems that do not experience a remarkable efficiency difference from day to night, this new class of equipment usually replaces daytime operations from air-cooled condensing units. In areas where there is a significant difference between peak daytime and outer peak temperatures, this type of unit is usually more energy efficient than the equipment it replaces.

Maps Ice storage air conditioning

Turbine gas turbine inlet cooling

Thermal energy storage is also used for combustion of gas turbine air conditioning inlets. Instead of diverting electricity demand into the night, this technique converts the generation capacity into days. To produce ice at night, the turbine is often connected mechanically to a large cooling compressor. During peak daytime loads, water is circulated between the ice pile and the heat exchanger in front of the turbine air intake, cooling the intake air to near freezing temperatures. Because the air is cooler, the turbine can compress more air with the amount of compressor power supplied. Usually, both the electrical power generated and the turbine efficiency go up when the incoming cooling system is activated. This system is similar to a compressed air energy storage system.