In solar hot water systems, water storage tanks are used to store the heat generated by solar collectors, sometimes referred to as "hot water storage tanks." The use of liquids (especially water) for heat storage is the most advanced and widely used theory and technology in various heat storage methods. In addition to having a larger specific heat capacity, the liquid used is generally expected to have a higher boiling point and a lower vapor pressure. The former is to prevent the aluminum alloy box from being transformed (into a gaseous state) while the latter is to reduce the storage Pressure on the heat container. In low-temperature liquid heat storage medium, water is the best, and therefore the most commonly used one.
Tell you about the advantages and disadvantages of domestic solar hot water system
interest
① physical, chemical and hydrothermal properties are very stable, we know it very well Angie aluminum box is very understanding, the use of technology to the oldest;
② can double as heat storage medium and heat transfer medium, heat storage system can be removed within the heat exchanger;
③ heat transfer and liquid properties are quite good, the common liquid, the largest specific heat capacity, coefficient of thermal expansion of small, small viscosity, it is suitable for natural circulation and forced circulation;
④ liquid - when the balance of gas temperature - pressure contact is very suitable for flat-panel solar collector;
⑤ rich history, low prices.
defect
As an electrolytically corrosive substance, the oxygen that occurs is prone to tarnish the metal and is a solvent with respect to a large number of gases, especially oxygen, so that corrosion of the vessel and piping is minimal;
② coagulation (icing) when the larger volume swelling (up to 10% dominated), easy to damage the containers and pipes;
(3) Above mid-temperature (over 100 ℃), its vapor pressure increases exponentially with the increase of hot water temperature, and heat and water can not be used for heat storage. Temperature and pressure can not exceed its critical point (373.0 ℃, 2.2 × 10Pa) , Such as the cost, the cost of heat storage temperature of 300 ℃ than when the heat storage temperature is 200 ℃ when the cost is 2.75 times higher.
The use of water as a heat storage medium, you can use stainless steel, enamel, plastic, aluminum, copper, iron, reinforced concrete, wood and other materials for heat storage containers, the shape can be cylindrical, box and sphere, Care should be taken for the corrosion resistance and durability of the materials used. For example, the choice of cement and wood as a heat storage container material, we must think about its thermal expansion, to prevent leakage due to long-term use of cracks.
Hot water storage tank Hot water storage tank is a storage of both heat and cold storage equipment. It was developed as a component in systems for supplying hot water, heating and air conditioning to buildings, primarily to dispatch the imbalance between power and energy so as to advance the heat utilization of the system and to meet the heat load The demand.
Due to the exothermic nature of the hot water storage tank (complete extrusion flow, complete mixing flow and some mixed flow), pressure conditions (open and closed), the number of tanks (single and multi-tank) Or vertical and horizontal or horizontal), structural materials and uses are not the same, can be divided into a variety of different types. The following only the first two points to introduce.