This Rockhampton Private Hospital accommodates 140 beds with theatre and casualty services.
The stand-alone laundry facility serves all the requirements of the hospital with a weekly laundry load of between 25 to 40 ton.
Laundry Hot Water Supply
The laundry equipment requires low pressure steam and hot water at a temperature of 60°C. Historically, hospital complexes have used centralised steam and hot water generating plant and distributed to individual buildings through a pipe ring main system.
With the shift away from coal and oil fuels, greater flexibility in plant configuration and equipment is available to reduce annual operating and maintenance costs. Designers have moved toward distributed systems, raising heat at the point of use in conjunction with traditional central schemes.
In most commercial laundries, steam is used directly for laundry steam operations and for raising hot water. For this hospital, advanced electric heat pump technology has offered costs effective means of meeting hot water requirements, thereby reducing the consumption of steam and size of steam raising plant. As a guide, Accent hot water heat pumps deliver between three or four times more energy in the form of heat, than is consumed electrically.
This high performance characteristic is put to good use in the laundry application, where the cost of raising steam either by gas or electricity is dramatically reduced. Substitution of heat pump technology for traditional methods shows energy consumption reduced down to less than 33% of direct heating and less than 26% of gas combustion heating.
Laundry Hot Water System
Fresh water from mains supply is fed to an open vented cold water storage tank at ground level. Pressurised cold water is supplied from this tank by pump to service water outlets and to an open vented 4,000 litre hot water storage tank.
Pressurised hot water is supplied to laundry equipment by secondary hot water supply pump.
The combined laundry hot water demand has been estimated to be 3,900 litres/hour. Heating is supplied by 3 electric hot water heat pumps linked to storage tank through a forced circulation primary hot water circuit.
The heat pumps are located indoor and are required to have air discharge ducted through the roof.
Accent equipment supply
Equipment supply included the hot water storage tanks, three hot water heat pumps and the primary hot water circulating pump.
The HeatWave series of hot water heat pumps are rated at 53KW output at 60°C delivery temperature under ambient conditions of 15°CDB.
The heat pumps were customised for this application by using Maneurop Scroll compressors in place of conventional reciprocating type. Scroll compressors have a vibration free rotary action, very high cycle efficiency and are more tolerant of continuous high outputs and extreme operating conditions.
These characteristics were considered ideal for the supply of hot water heat pumps into a location such as Rockhampton involving prolonged high air temperatures. These hot water heat pumps are expected to log many hours of operation each year, and robustness and reliability in arduous conditions has been a key consideration in component selection.
Fans have been modified for ducted discharge through the roof in accord with site requirements.
The tank designed by Accent Water & Energy incorporates metal sheathed polyurethane insulation outer skin, ball value level make-up water control, thermostat controller and with primary hot water connections to the lower half of the tank.
The tank features a primary hot water sparger (perforated pipe across width of tank) to promote stratification of heated water – isolating an undisturbed zone of 60°C hot water in the upper half of the tank so avoiding mixing with the colder blended make-up zone below.