CASE STUDY: Pembroke College, University of Cambridge

  • Traditional hot water filled radiator system
  • Bespoke Brass fittings to complement existing hardware

  • Independent control over individual rooms

Prefect Irus  – the centrally controlled energy management system from Prefect Controls has been installed as a trial in 30 rooms at Pembroke College Cambridge.

Pembroke’s Robert Griggs took up the post of Building Manager in 2014. It soon became obvious to him that the college accommodation was under-heated and that the old pipework and plant room wasn’t coping with the demands of 21st century student accommodation.

From the Prefect website, Robert saw the extensive work they had carried out at Bristol University and a visit to the South West confirmed that Prefect could be a good fit for the project he had in mind.I have been to Bristol, looked around and was aware of their estates set-up which seems to be very good, so that was of interest because it’s a big site. If they were going to install the system, then that gave me the confidence that it was probably a system worth looking at.” He said.

Work progressed at Pembroke and the antiquated plant room has been renewed, the diameter of the underground pipework and resilience of the circulation system has been increased and as a result no rooms are now out of reach from heat. Robert decided to install the Prefect Irus system on a test basis in 30 rooms to check how it performed when controlling the newly installed radiators. The room-side kit comprises a Prefect Irus control unit, PIR sensor, thermal drive Valve and power unit. “This is a trial really. We probably have 400 units on site here and a further 300 off site and if we can offset some of the investment we have made over the last two years on plant rooms and distribution pipework, by reducing our energy consumption, whilst still having comfortable rooms, then that seems to be a sensible approach.” Robert commented.

He continued, “It is predominantly a wet system, but we have one area that is over our historic 14th century, what is called the old library, and it has an incredibly ornate plaster ceiling, so there is no way there will ever be a wet system above that ceiling, just in case! In there we have installed panel heaters, still on the Prefect system, in fact Prefect installed the heaters. When we recommissioned the heating system this year, suddenly we were getting more heat to areas than we had before, it was noticeable, because you walked by and there were a lot of windows open. We then commissioned the Prefect system, and the windows closed, and it seems to be working well now.”

Students within the test zone seem to be happy with the level of comfort in their rooms and there have been no complaints about temperature or operating the controls, “I deliberately didn’t provide instructions on how to use the system. When I went round the rooms everybody had started using it, it is intuitive really, I mean they are intelligent people but none the less it is intuitive, so that is good.” Robert remarked.

Prefect Irus monitors a room’s temperature and occupancy and if it is vacant for a period of time the heating is reduced automatically.

“The system sets back to a predetermined temperature – previously that was probably the maximum temperature we ever achieved in those rooms.” He says.

When occupiers return they can adjust the temperature to their desired level or the system will automatically raise temperatures. This monitoring of occupancy helps managers to measure energy usage over a period of time and ultimately this will help to negotiate better deals with energy providers.

Control of temperature is one way to cut energy cost but Robert is convinced that heating rooms only when they are occupied, is a far more effective way to ensure comfort AND cut costs. “There are two elements to this for me,” he said.  “One is energy saving and reducing our carbon footprint, but the other thing is to ensure that people are comfortable in their rooms. We have students from all over the world coming here, so the fact that the students now feel they are in control of the temperature in their room is very important, and yet, we are saving more energy than we would if we were using thermostatic radiator valve, simply because they would be set on 2 or 5 and left – whereas now heating is only actually on when students are in their room. The fact that they can turn it up when they come in means they feel in control, but the significant thing for me, is that it’s not been on when they are out – or only at a very low level.”

“There are two elements to this for me, one is energy saving and reducing our carbon footprint, but the other thing is to ensure that people are comfortable in their rooms.”

Prefect Irus is not only unique in the way the software monitors individual rooms, the specification for the hardware is also bespoke – In the public areas at Pembroke College where Prefect Irus has been fitted, unique brass fronted movement detectors and thermostats have been manufactured to be in keeping with the historic style of the building. The mains borne signaling operation for Prefect Irus also makes it ideal for these situations, Robert was particularly impressed with how the Prefect team performed, “The Installation went very well, I spent quite a lot of time with the guys who were working on site because these are not just standard rooms and the rooms on the staircase are a combination of oak paneling and plaster finish. The mains borne signaling is a neat idea and arguably requires less wiring. We looked very carefully to identify the wiring routes and how we could hide as much as possible. To be fair they followed the plan and came up with their own ideas that we discussed as well, so the installation went very well”.

So, following an extensive revamp of plant room and infrastructure, is this 14th Century college confident that 21st century students are enjoying the most effective control for their environments? “We looked at other systems, but we couldn’t quite find one that did what we wanted it to do as well as Prefect did. There are other systems on the market, but Prefect seems to give the best user control and the most visibility for me. I can sit at my desk and see what is happening in various rooms. It’s fair to say there are some systems out there that can do what the Prefect system does but they are a lot more complex and a lot of what they can do is unnecessary”

Robert continued, “When I came here we used to issue electric heaters to supplement the heating system, I couldn’t believe it! I have now got all of them back because the heating is working to a level that people have never experienced before, and they were 2-3 Kw heaters with upto 200 being issued!”

Robert is confident that Prefectirus will perform to his expectations and has plans to widen its use across other parts of the college accommodation and potentially into new developments that are on the horizon.