Case Studies
CRODA CHEMICALS
Croda Chemicals at Leek as part of their oil processing were using a large water cooling tower to control the oil temperature. The cooling tower was due to be replaced with a 150kW closed cooling system to reduce the risks and costs associated with an open system.
Although the kW rating was relatively low the cooling water had to be returned within 5C of ambient based at 35C. Several vendors suggested adiabatic systems in order to keep the cooler at a reasonable size and cost although Croda were not keen on this type of cooler design.
Forward and Clixcoolers Ltd offered a bespoke design modular dry cooler using efficient aluminium multiport tube in order to keep the size practical for the footprint available. Fitted with variable speed drive this offered the client much better control and energy savings. This along with price and several other advantages like the ease of cleaning, easy to maintain and long service life was decisive for Croda.
The unit was installed and commissioned on time and on budget with the client having the reassurance of a 3 year warranty and service plan in place.
THAMES WATER
Thames waste water had experienced over-heating and leaks of the cooling systems for their combined heat and power generating systems operating at various waste water plants. These issues typically caused the systems to experience unscheduled downtime for approximately 330 hours per year, this in turn resulted in a loss of revenues in the region of £13,000 per site per year.
As part of the replacement program of the traditional dry air coolers Thames Water were keen to eliminate these unscheduled shut downs and look at new cooling technologies that could address these problems.
Clixcoolers had a number of meetings with Thames Water and visited several sites experiencing issues in order to gain a better understanding of the problem. It was decided that Clixcoolers would design and quote for the first two coolers due to be renewed, these were situated at the Thames Water Swindon sewage treatment works.
The 'Clixcooler' design was chosen in preferrence to traditional type dry air coolers due to several factors, these being; its unique modularity offered reliability, improved performace, ease of maintenance and cleaning, long service life, no disruption when accessing site as no heavy lifting equipment is required.
The two new coolers were successfully installed and commissioned on time without issue. Thames Water have now embarked on an extensive replacement program of coolers at their combined heat and power sites, they have selected Clixcoolers as the preferred design.
SEVERN TRENT WATER
Client Severn Trent waste water had experienced a winter freeze up on one of their combined heat and power generator cooling systems at Monkmoor Shropshire due to lack of control over the two cooling systems.
The system has two coolers one for the recovered heat that is utilised by the digester and controls the engine temperature, a second cooler is used to cool the engine charge air cooler.
The duty of these coolers is 420kW and 110kW respectively. The existing coolers were traditional forced air coolers (dry coolers) which were cased together one in front of the other and utilised the same cooling fans.
It was this design that caused the problem, the digester utilises clean water to which no glycol can be added and is stopped from freezing by the addition of an electrical back up heater within the cooler. The charge air cooler is a water glycol system with the back up of a cooler heater.
During the winter period whilst the engine was running the demand for the recovered heat was at a peak so no cooling of this system was required however because the charge air cooler still required cooling the cooling fans were operating at full, this drove the primary circuit temperature so low that the back up heater could not compensate and caused the freezing of the water within the cooler.
Clixcoolers limited remit was to re design both coolers so they would operate individually with total control of both circuits whilst only having the limited footprint of the original coolers available.
Clixcoolers limited successfully re designed the coolers with their patented modular design. Each cooler had a variable speed drive to control the two fans required and these were linked with the comap engine management system to give total control of both systems to the client.
Additional benefits for the client included energy saving, longer service life of the coolers & motors, easily maintained and cleaned and a 3 year warranty.
