Ships HVAC Systems ? Energy reduction

The energy needs of modern warships are high and one of the main consumers is the ships air conditioning and ventilation system. Current demand, including design for extreme ambient conditions, increased fresh air requirements and internal

Date: Issue 33 - February 2012

The use of Active Chilled Beams is another proven technology from land applications suitable for naval environments. Using higher temperature chilled water and driven by fresh air from the NBC Air Filtration unit, this approach can significantly reduce ductwork and save energy through higher CWP evaporating temperature and reduced air movement.

The Chilled Water Loop is yet another aspect of the system that can deliver energy savings by switching from fixed to variable volume flow. Using 2-way valves rather than the usual 3-way will decrease the demand for chilled water at reduced loads, and this can be sensed to reduce pump flow. At 80% flow the pump only consumes close to half of the full flow power.

With more than 125 years experience in the HVAC field and the significant experience in the energy saving solutions in both land and commercial ship applications, Johnson Controls owns the knowledge and technology necessary to meet the energy saving requirements of modern navy environments.

An example is the Johnson Controls oil free compressor, now in service for over 10+ years. The use of Active Magnetic Bearings to support the compressor / motor shaft allows the chilled water plant to run completely oil-free, avoiding all typical problems it brings. The motor is driven using a Variable Speed Inverter Drive unit that allows the compressor impeller to run at optimum speed to maximise the efficiency and performance. The ability to use no oil has numerous advantages, in addition to a less complex system design, reduced maintenance and increased system reliability (up to 60,000 hours), as there is no need to maintain an artificial condensing pressure to drive oil around the system. The system can therefore operate at the ?real? sea water condition and at low load this can result in savings of up to 80% compared to conventional systems.

For more information, please contact carl.bookless@jci.com
Visit us at: www.johnsoncontrols.com/marine