1. Case Study: Marks & Spencer Oxford Street
Copyright © 2010 EDSL
State of the art building simulation software...
Case Study: Marks & Spencer
Oxford Street
Environmental Design Solutions Ltd

2. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...

3. M&S Oxford Street State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
The Brief:
Calibrate a base model using metered consumption figures – “existing building”
Apply changes required in the refurbishment brief to predict energy consumption – “proposed building”.
M&S Oxford Street
Information required to create base model:
Drawings
Constructions
Usage patterns
Internal gains – lighting, occupants, equipment
Plant operation
We were to use the information provided by the client to build up the base model, then tweak this through client collaboration and ensure the base model is as close as possible to metered data
There were elements of the building operation which were known, for example the footfall had been measured, plant & store hours were known, etc. The calibration in line with metered data helped to ensure the elements which were less well known were modelled correctly.
In broad terms, we needed the items listed in order to build up the model. We will look at more detailed requirements shortly.

4. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Considerations…
Some aspects of operation will affect heating & cooling demands:
escalators
cooling effect to space from cold aisles
plinth heating of refrigeration units
small power, e.g. tills
Some items will not:
Some of these demands would be included into the simulation to allow for the heat gains to the space, in turn these will then affect the heating & cooling demands on the space as well as the associated fan & pumps energy consumption figures. Cold aisle spillage & low level heating was accounted for and dealt with appropriately.
Some demands were input from measured data provided by the client and were added to the energy consumption figures post-simulation, for example lift power consumption. The consumption of the refrigeration units was calculated from data provided by refrigeration manufacturers.
refrigeration compressor energy consumption, including cold rooms & freezer rooms
lifts

5. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
The table shows how the client wanted the information broken down
Energy Sub-System
SITE – Pantheon Marks & Spencer
From results of Thermal Modelling for original building (kWh/m2/yr) ( C)
From results of Thermal Modelling of the refurbished design (kWh/m2/yr) (D)
Electricity
Gas
Heating & hot water -
Cooling
Fans and pumps
Humidification
Lighting
Office empty
Catering Gas
Catering electricity
Other electricity
Computer room
Total gas
Total electricity
Total Energy
Detailed information is required for each field in order to accurately predict consumption for each sub-system.
Benefit of this calibration is to ensure that each end use category can be shown to be behaving correctly, i.e. heating & cooling consumption is as expected, fans & pumps, lighting loads, domestic hot water, small power can all be compared with monitored data by the client to give them confidence the quality of the analysis, and thus confidence in future predictions.

6. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Indication of detail required
Heating & cooling efficiencies
Distribution losses
Pipe index circuit length & pressure drop
Fan SFPs
Hot water consumption, generator efficiency & distribution losses
Lighting installed density
Daily opening hours with hours of plant operation
In order to effectively model the plant, we need information about each of the components as well as full details of what’s happening in each zone within the building.
Method of heating, cooling & ventilation
Ventilation rates

7. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Services Summary
CAV heating & cooling
Poor heating & cooling efficiencies – 65%, COP of 2.5
No heat recovery
Supply Fan SFP = 3W/l/s, Extract Fan SFP = 1W/l/s
Lighting 40W/m2 sales floor, 36W/m2 back of house
1.2l/s/m2 Fresh Air, 10 l/s/m2 total supply
The existing building was very inefficient, with high electrical consumption through poor fans, lighting and cooling, and high gas consumption due to the inefficient boiler.

8. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Typical services schematic
The heating, cooling & ventilation system used in the building was a CAV – Constant Air Volume system – with around 10% fresh air

9. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Typical services schematic
A fair amount of heat was delivered to the space due to the operation of the fans. Clearly, reducing the amount of heat generated by the fans and thus delivered to the space will reduce energy intensive cooling demands.

10. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
The refurbishment of the building had already commenced by the time we were approached, so availability of data was limited
Energy Sub-System
SITE - Pantheon
Thermal Modelling on existing building (kWh/m2/yr)
Metered Results (kWh/m2/yr)
Electricity
Gas
Heating & hot water -
112.65
Cooling
84.8
Fans and pumps
123.97
Humidification
Lighting
126.38
Office empty
Catering Gas
Catering electricity
20.7
Other electricity
66.56
Computer room
Total gas
184.75
Total electricity
422.42
339.74
Total Energy
535.06
524.49
With the data we had we attempted to match metered fuel types and total energy consumption
We were not provided with full sub-metered consumption data for the job, rather totals by fuel type.
With the refurbishment already underway our client was stretched to supply further information regarding the old systems initially installed, so there was much collaboration required to try to match meter readings.
Eventually we mutually agreed to move on with the next stage of the work, given our total consumption figures were within 2% of monitored data.

11. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
With the base model complete, the next step was to include the changes put forward by our client
Areas of investigation
Lighting
Replacing heating & cooling plant
Installation of local VRF
Changes to occupancy levels
Improved fan efficiencies
Addition of new staff & customer cafes
Addition of a new bakery & hot food sales area
Extra refrigerated aisles
There were many changes to be included as a result of the refurbishment, and if required we could have looked at each item separately to see its direct effect, in this case the client wanted all changes included at once.

12. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Summary of changes
CAV heating & cooling with local VRF
Heating efficiency from 65% to 80%
Chiller COP from 2.5 to 2.8
60% improvement in Fan SFPs
Sales lighting from 40W/m2 to 30W/m2
Back of house lighting from 36W/m2 to 8W/m2
Ventilation rates unchanged
It was agreed that it would be best to target the most CO2 producing elements during the refurbishment, so electrical consumption from fans & lighting were slashed, both items having a double impact in reducing heat gains to the space. The boiler and chiller were upgraded although both could have been improved further. The same CAV system was employed almost throughout using the same total volume flow rate, however local VRF units were also introduced to problem areas, meaning air could be diverted away from those areas to other parts of the store as necessary.

13. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
With the changes made we could analyse for consumption
When comparing results it is clear to see the areas of change
We can view results for the whole building energy consumption or CO2 results
This chart shows total energy consumption for the existing model, broken down to heating, cooling, fans & pumps, lighting, small power (i.e. heat gains to the space) and in this case ASP (power not contributing to heat gains) & catering power.
If required any of these could be subdivided by fuel type.

14. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Just looking at the consumption & CO2 for environmental treatment elements, we can see that total energy consumption has dropped by 46% and CO2 has dropped by 50%
In terms of environmental treatment, i.e. just end-uses controlling the environment within the building, savings can really be seen
Both energy consumption and CO2 emissions have almost halved
Whilst heating efficiency has been improved, heat gains to the space have been slashed so the heating demands are higher but being met more effectively

15. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Summary of improvements
Energy consumption reduced by 21%
CO2 emissions reduced by 22%
All this despite the inclusion of:
A new Café
A new Staff Kitchen
A new Bakery
Local VRF units
Increased footfall

16. Environmental treatment total consumption reduced by 46%
Copyright © 2010 EDSL
State of the art building simulation software...
Summary of improvements
Environmental treatment total consumption reduced by 46%
Environmental treatment total CO2 reduced by 50%

17. State of the art building simulation software...
Copyright © 2010 EDSL
State of the art building simulation software...
Benefits to end-client:
Expected energy consumption broken down by fuel type & end use
Indication of expected cuts in running costs
Marketing potential

18. Environmental Design Solutions Ltd
Copyright © 2010 EDSL
State of the art building simulation software...
Environmental Design Solutions Ltd