Water Heating Products
A de-superheater is essentially a heat exchange circuit connected to the milk cooling refrigeration unit and is used for heat recovery.
A dairy shed's refrigeration unit removes heat from milk and then loses that heat in the condenser. The condenser changes high pressure vapour back into liquid, allowing heat to be given up to the air. A de-superheater can be added to this circuit to remove the sensible heat (heat before the gas condenses) from the superheated refrigerant.
De-superheaters recover up to 20% of the available waste energy, depending on the type of refrigerant. This can heat water up to 60°C again depending on the type of refrigerant, flow rate of the water being heated and the type of system installed single pass or re-circulating.
Paybacks for this technology are good compared to other heat recovery options, but the amount of heat recovered is smaller.
This is a good option for many farmers where capital costs of other options may make paybacks too long. The installation cost of this technology can range from $2,500 to $4,500 and may be more practical to be owned by a farm owner rather than a share milker.
To determine if your farm is suitable for a de-superheater just complete the water-heating section of the Dairy Efficiency Calculator. To find out more about the de-superheater, go to the following website www.dts.co.nz.
These systems collect the waste heat from the refrigeration unit's air-cooled condenser and convert the incoming cold water into stored hot water.
This is effectively achieved by a plate heat exchanger, which is combined with a heat pump to provide a greater volume of hot water at a higher temperature (85 - 90°C) than other recovery systems. This system uses electricity, but it is a much smaller amount compared to that used in direct (element) heating. The units can be retrofitted to the existing refrigeration and hot water systems.
These systems should be able to provide almost all of the hot water requirements for your dairy farm, making this a great technology choice if the paybacks are viable. Depending on the size of the unit the installation cost can range from $11,000 to $12,500.To determine the payback for these systems for your farm just complete the water-heating section of our Dairy Efficiency Calculator.
Find out more about the Heatcraft‘s Mahana Blue™.
Hot Water Heat Pump
Heat pump water heaters use heat from water or atmosphere, rather than from the refrigeration plant and use electricity to increase the quality and quantity of the heat transferred. Typical heat pumps can achieve temperatures of 60°C depending on the technology and refrigerants used. This technology is very efficient (1 kWh of electricity input provides 3 to 4 kWh of heat output). To achieve 85°C water, standard electric elements can be used when the heat pump maximum temperature is reached. This technology can be installed as a retrofit or completely new system.
Note that there are other efficient systems on the market that often use combinations of water condensing, superheat recovery and heat pump technologies as Enersol or Eureka product.
Depending on the technology and size of the unit the installation cost range from $8,000 to $11,000. To determine the payback for a these systems for your farm just complete the water-heating section of our Dairy Efficiency Calculator.
Solar Water Heating
There are different types of solar water heating systems that suit dairy farms. In all systems, solar collectors heat the water on the roof of the dairy shed. There are different technologies of collectors with different range in efficiency and price. However, solar water heating systems can be divided in two families: thermosyphon and circulating systems.
A thermosyphon system utilises the natural convection of heat. The solar collector must be located below the level of the insulated water storage tank. Cold water from the lowest of the tank enters the collector, is heated and rises to the upper section of the storage tanks. At the same time cold water enters the collectors to replace the existing heated water. The process is self-regulating in that it continues until no more heating can occur.
Forced flow or circulating system incorporates an electric circulation pump. This allows the collectors to be placed to take the best advantage of the sun, independent of the location of the storage tanks. The disadvantage is the capital and running cost of the pump and any problems if the pump or its control system was to fail.
There are considerations to be made when choosing the type of solar water heating system for example: a full storage tank on the roof may require reinforcing the roof or in a cold region, anti-freeze systems using an additional heat exchanger and glycol solution may be required which will increase the capital cost.
Depending on the technology and size of the unit the installation cost range from $650/m2 to $1,350/m2*. To determine the payback for a these systems for your farm just complete the water-heating section of our Dairy Efficiency Calculator.
*All installation costs have been provided by relevant suppliers. Genesis Energy makes no warranty as to the accuracy of this information.