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ENERGY EFFICIENCY CASE STUDY


Five not-quite-so-quick wins


‘We need the quick wins in Portland House because of its uncertain future, but for some of the other buildings in LandSecurities Victoria portfolio, payback can be longer,’ says Camsell. Adjacent to Portland House is the Cardinal Place development, which includes 80 and 100 Victoria Steet and 16 Palace Street. The scheme was completed in 2005. According to Camsell and Barrett, it is well-designed and the buildings run well; even so, the dynamic duo have made some serious energy savings:


In hard cash, the units were costing almost £30 in electricity a day for doing nothing. Camsell had the units disconnected at no cost


1.Turn off the maintenance transformers A feature of 80 and 100 Victoria Street are the 110V transformers dotted around the buildings. These were installed as part of the buildings’ high specification fit out, ostensibly to allow the maintenance teams to plug in low voltage power tools. However, in his three years running the building, Camsell had never seen the transformers used. ‘Contractors either use a 240V drill or they have their own portable transformer,’ he says. The units felt warm to the touch. ‘Each unit was pulling 0.6amps with no load,’ he says. Camsell did a quick calculation: in total there are approximately 100 transformers, which meant a total load of 60amps at 240 Volts, or 14kW. In hard cash, the units were costing almost £30 in electricity a day for doing nothing. Camsell had the units disconnected at no cost.


2.Turn off the car park lighting There is a car park situated beneath Cardinal Place. The proposal is to fit the same sensors used for the escape stairs in Portland House to control the car park lighting. ‘There are about 300 light fittings and the proposal is expected to save about £10,000 a year, with a payback of about 1.5 years,’ says Barrett.


3.Change the humidifiers Maintenance of all the building’s steam humidifiers was proving expensive, so Camsell and Barrett decided to test a new system manufactured by Gibbons


Typical costs Equipment cost


Maintenance costs Repair costs


Gas inspections Total over 20 years


Average cost per year


Steam £0


£2,500 x 20 = £50,000 £19,000 x 6 = £114,000 £500 x 20 = £10,000 £174,000 £8,700


Rotary £90,000


£600 x 20 = £12,000 Included above £0


£102,000 £5,100


Maintenance cost comparison of steam versus rotary humidifier for four units over 20 years 44 CIBSE Journal November 2011


Humidification, which atomises water to an ultra-fine mist in the airstream. Barrett did some calculations: ‘It was clear the savings from using the rotary units are reasonably good, based on maintenance costs alone,’ he says. They decided to install the rotary unit in one


air handling unit at Palace Street. As soon as the system was up and running it was obvious it was generating additional energy savings. ‘We’re not using energy to raise steam for humidification and we don’t have to cool the humidified air to achieve satisfactory supply conditions,’ says Barrett. Accurate results will be available after a full year because the humidification requirement varies over the year. However, ‘initial indications from Palace Street indicate substantial savings in energy’, he says.


4. Ensure chillers run at full load There are 10 chillers on the roof of 100 Victoria Steet. However, rather than have one chiller running efficiently at full load, the control strategy was letting each chiller decide its own load independently of the others. The control strategy was changed to allow the building management system to decide how many chillers were needed, based on the chilled water return temperature. ‘We only run the minimum number of chillers needed for the load, which saves a lot of energy,’ Camsell says.


5 Extend Earth Hour Every year conservation body WWF encourages everyone to turn off their lights for an hour at 8.30pm on the last Saturday in March for its Earth Hour campaign. LandSecurities encourages its tenants to participate in this initiative. The three-hour blackout saves £180. However, if this initiative was rolled out every night, Barrett estimates the combined electricity savings of 80 and 100 Victoria Street would be in the region of £65,000 a year.


www.cibsejournal.com


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