Tag: lighting

Lighting in Daventry.

A while ago (as outlined in Lighting – do we have too much?) I started to look at the amount of lighting on our Daventry site.  For various reasons it has taken some time to make any meaningful changes, but at last we are beginning to make some progress.

Surprising discovery number one – we had no light switches for a quarter of our warehouse – even when no one was around we had to leave 3kW of lights on.  Whilst this is only for a small proportion of the year it is still waste.  The lights were controlled by a photocell, unfortunately somewhere along the line a Health & Safety survey had declared that the lighting was insufficient and, instead of changing the levels the detectors were covered up.  This meant that other than tripping the circuit breakers, the lights could not be switched off; even on the brightest of days.

The first step was therefore to sort this ridiculous state of affairs out.  We have now installed some new photocells which can be changed remotely if the initial levels are incorrectly set.  The payback time on this is less than 12 months even if the light is only bright enough to switch them off for 4 hours each day.  The only fly in this ointment is that H&S police have again determined that the light levels initially set were incorrect, and, rather than resetting to the correct levels, they have been turned to permanently on!  A task for the next week will be to sort this problem out.

Other areas have been identified where lights are left on for no reason.  Despite being only a few fluorescent tubes (relatively small in number compared to the aforementioned warehouse) they still represent substantial savings.   The first of these areas was the Plant room – visited only by maintenance staff, and therefore it should have been better controlled.  Unfortunately, unless you are in the room you can’t tell whether the lights have been left on; it was estimated that there were about 158 hours of extra lighting each week in this area.

The second area is a small office in the middle of the warehouse that has no permanent occupant and is subsequently visited by various members of staff, none of whom appears to be capable of turning the light off when they leave.  This 200W of lighting is left on unnecessarily for about 144 hours every week.  The answer to both of these has been the addition of PIRs (Passive Infra Red detectors) – motion detectors.  I think that you can get too carried away with motion detectors and see them as the answer to everything, but in some cases, for example when there are lots of different occupants using a room, only some whom will regularly turn the light off, they can be beneficial.  Both of these projects had estimated payback times of less than 12 months.

The final change that has been made has been a no cost solution and is the most obvious. A member of the maintenance team was asked to survey the lighting of the entire site and, in addition to the number, type and power of the lights, estimate hours of use and the amount of wastage.  As a consequence it occurred to him that one of the areas was visited for approximately 1 hour per week but that all three of the 70W tubes were on permanently.  He was usually the only one to visit the room and has now promised to turn the lights off when the room is not in use, a saving of 1800kWh per year.

Other areas have been singled out as needing a motion detector – these include the toilets, the tea room and the locker room, but I am having less success in getting these fitted – it is starting to become a bit of a mission!

I have now started to look at the rest of the sites within the business unit as part of the requirements for our participation in the Carbon Reduction Commitment Energy Efficiency scheme (CRCEE) and have learnt more about lighting than I ever expected.  Details to follow..

Lighting – do we have too much?

As mentioned in a recent article, we have had a couple of surveys conducted on the site, and both immediately singled out lighting as an area where we can cut our expenditure / consumption.  This is an obvious place to look really as we are a large warehouse with a lot of lights. 

As a brief intro, we essentially have 5 warehouse areas built over the last 20 years or so, of different heights, lit by fluorescent tubes for 24 hours a day, 7 days a week; such is our working pattern.  In addition, we have a few office areas that are, in the main, occupied only during office hours. 

Whilst I will admit there is plenty we can do to cut our lighting bill, I think those auditing the site are under the impression that it is a bigger problem than the data actually suggests. The Carbon Trust report estimated that lighting accounted for 27% of our electricity consumption, and this is what I have discovered to date.

  1. We have over 500 tubes of varying sizes on site.
  2. If a room lit by fluorescent tubes is unoccupied for more than 9 minutes it is more energy efficient to turn the light off.
  3. Getting people into the habit of turning off lights when leaving a room is difficult, but not impossible – I deem this a work in progress.
  4. Two of our warehouses which were built in the last 10 years were fitted with daylight sensors – these warehouses have higher roofs and are generally lighter.
  5. These sensors are in an unsuitable place, and in failing to control the lighting acceptably they have been covered up.
  6. There are no light switches for these warehouses; the lights are on all day, every day.
  7. Indoor lighting is responsible for approximately 11% of our consumption, with outdoor lighting on a sensor and adding about another 0.5-1%.

As stated at the beginning, there are measures we can take, but at only 11% of consumption, they will have a limited effect. I will update you with the results of these efforts at reducing our lighting bill in a later post.