Measures for Demand Improvement

Contents

1. Introduction

2. Methodology

3. Results Summary

    3.1 Insulation

    3.2 Lighting

    3.3 Heating

    3.4 Ventilation

4. Conclusions

1. Introduction

As part of the first step of our methodology, the demand side study, various energy efficiency measures have been selected and analysed concerning their effectiveness and profitability for construction villages.

These energy efficiency measures deal with the following areas in which reductions in energy demand can be achieved:

1)       Insulation

2)       Lighting

3)       Heating

4)       Ventilation

Another focus of the demand side study will be the improvement of environmental comfort inside construction site accommodation, which can be achieved using the assessed measures.

This is especially of interest for introducing ventilation in various spaces of the construction village, since there are no energy savings associated with ventilation systems but enormous improvements in thermal comfort.

2. Methodology

In order to reduce the energy demand of construction villages and improve occupant’s comfort at the same time the current insulation envelope, the heating, lighting and ventilation system of the site accommodation has to be studied. All four areas are analysed and various solutions, which are based on the implementation of energy efficiency measures, are identified. These solutions are then evaluated regarding enhanced energy savings as well as changes in environmental comfort.

At the end the results for all solutions (measures) are summarised into tables and are therefore available for construction companies to choose appropriate measures to improve their construction villages.

The results summarised cover:

Energy savings

Investment

Payback Period

Other Benefits

All results were gained by studying a standard sized cabin (9.5m *3m) or office space (4m *3m).

A detailed study on insulation, lighting, heating and ventilation can be found by following the corresponding links on the website.

Additionally there is a link on other measures, which briefly describes additional measures that can contribute to a reduced energy demand in construction villages.

The methodology diagram can be seen as follows:

Every analysis and evaluation of the various energy efficiency measures has been carried out keeping in mind the following comfort standards for the construction site accommodation.

These standards are derived from the Health and Safety Regulations as well as from CIBSE Guide A and B2.

The comfort standards we have considered can be seen from the table on the right.

Comfort Standards

Dry resultant temperature	Minimum temperature	16° C
	Comfort temperature	20° C

Illuminance	In offices	500 lux
	In other areas e.g. canteen	200 lux
	Outdoor	20 lux

Fresh air rate per person	Minimum air rate	5 litres/sec
	Recommended air rate	8 litres/sec

CO₂level	Comfort CO₂ level	< 0.1%

3. Results Summary

The following tables summarises all solutions, based on the implementation of energy efficiency measures, which have been identified during the process of this project. Additionally the identified energy savings, capital investment and payback period (where feasible) for each solution are listed.

3.1 Insulation

Conventional and state-of the-art cabins have the following characteristics in terms of insulation.

	Construction ^a	U-value ^b W/m²K
Wall	· 50mm mineral wool insulation	0.67
Floor	· 60mm mineral wool insulation	0.50
Roof	· 70mm mineral wool insulation	0.54
Door	· 40mm mineral wool insulation	0.85
Window	· Single glazed with aluminium frame	5.5

U-value for typical conventional cabin types

Note:

^a based on specification of Containex Ltd

^b U-values do not comply with the Scottish Building Regulations for buildings.

	Construction^a	U-value ^b W/m²K
Wall	· 80mm mineral Polyurethane	0.35
Floor	· 100mm mineral wool insulation	0.35
Roof	· 100mm mineral wool insulation · 40mm Polyurethane sandwich panel	0.25
Door	· 40mm Polyurethane insulation	0.66
Window	· Double glazed with PVC frame	2.7

U-value for state-of-the-art cabin types

Note:

^a based on specification of Lidney Containers Ltd

^b U-values comply with the Scottish Building Regulations for limited life limited life buildings

The following table summarises the results obtained considering energy efficiency and environmental comfort of construction villages by improving the insulation envelope of transportable accommodation used on construction sites.

SOLUTIONS

ENERGY SAVINGS

COST

£ ^a

PAYBACK PERIOD

yrs ^b

COMFORT BENEFITS

INSULATION

· Replace conventional cabins with state-of-the- art cabins

60 – 70

Buy

5,000

Hire

40 ^c

<22

Improved thermal comfort through:

· Increased dry resultant temperature

· Increased surface temperatures

· Reduced air infiltration

· Reduced relative humidity

Improved acoustic insulation

Limitation of surface condensation

Note:

^a for 9.5m ´ 3m cabin,

^b based on 10 pence per kWh energy costs; for buying a cabin

^c based on long-term hiring; £30 per cabin per week for conventional cabins

3.2 Lighting

The following table summarises the results that are gained from the detailed study of various energy efficient lighting equipments and strategies.

	SOLUTIONS	ENERGY SAVINGS %	INVESTMENT £ ^a	PAYBACK PERIOD yrs ^b	OTHER BENEFITS
INTERNAL LIGHTING	Install T5 fluorescent tubes instead of T8 and T12 tubes	38 - 45	10 – 15	< 1 ½	· Reduced carbon emissions · Lower mercury content · Small product dimensions result in less material, packaging, weight, transport and recycling volume
	Install high frequency ballasts on all luminaires	20 - 30	30 - 70	< 15	· Reduced carbon emissions · 50% longer service life · Silent operation · Absence of flicker · Automatic switch-off of faulty or end-of-life lamps · Reduction in weight
	Install PIR sensors in intermittent occupied areas ^c	65 – 90	20 – 50	< 1 ½	· Reduced carbon emissions
	Install automatic daylight control in offices	50 - 75	100 - 200	< 10	· Reduced carbon emissions · Uniform illuminance
EXTERNAL LIGHTING	Install 250W High Pressure Sodium lamps with photocell control	80	100 - 130	< ½	· Reduced carbon emissions · 300% longer service life
	Install Halogen floodlights with photocell and PIR control	75	10 - 70	< ½	· Reduced carbon emissions

Note:

^a cost per equipment, installation cost neglected

^b based on replacement in existing cabin; electricity cost 10 pence/kWh

^c e.g. toilets, drying room, office kitchen, canteen, meeting room

3.3 Heating

The following table summarizes the results that are gained from the detailed study of various energy efficient heating strategies.

	SOLUTIONS	ENERGY SAVINGS %	INVESTMENT £ ^a	PAYBACK PERIOD yrs ^b	OTHER BENEFITS
HEATING	Install Programmable controllers on existing 2 kW heaters	50	60	< 0.6	· Reduced carbon emissions · Control over group of heaters · Equal comfort temperature in all areas
	Install Programmable Thermostat on existing 2 kW heaters	50	43	< 1 ½	· Reduced carbon emissions · Occupants can alter temperature level
	Install 1.5 kW heaters with automatic temperature control panel	50	130	< 2	· Reduced carbon emissions · Reduced size of heater
	Install Over-door Heaters at main entrance doors	-	150	-	· Reduced carbon emissions · Reduced infiltration level

Note:

^a cost per equipment, installation cost neglected

^b based on the fitting of a new cabin; electricity cost 10 pence/kWh

3.4 Ventilation

The following table summarizes the results that are gained from the detailed study of various energy efficient ventilation strategies.

VENTILATION REQUIREMENTS

ac/h ^a

REQUIRED FLOW RATE

m³/h

VENTILATION SYSTEM AND CONTROL OPTIONS WITH LOW ENERGY DESIGN

INVESTMENT

ANNUAL ENERGY USE ^b

kWh

CABIN OFFICES

1.0

(1.6)

71.25

(114)

With the small requirement in offices (< 2 AC/hr), natural ventilation can be used and the opening and closing of windows and doors manually is sufficient to provide the required fresh air rate.

Nil

MEETING ROOM

2.5

(4.0)

178.1

(285)

Option 1: Natural ventilation can be used if the door is to be left

open for meeting duration.

Option 2: If meetings are to be conducted with closed door for more than 1 hour with 10 people or more, then ventilation fan with flow rate of 180 to 285 m³/hr with heat recovery is recommended.

- Ventilation system to be fitted with occupancy sensor

290.06

(with 75% efficiency)

30.45

148.7

TOILETS

2.0

(4.0)

142.5

(285)

Ventilation fan with flow rate of 143 to 285 m³/hr range is recommended.

- Ventilation system to be fitted with controls with on/off occupancy sensor (Passive Infrared + Timer)

50.00

44.10

28.6

CANTEEN

6.0

(10.0)

427.5

(712.5)

Ventilation fan with flow rate of 428 to 713 m³/hr with heat recovery system is recommended. (Cost and energy use is calculated based on fan with maximum flow rate of 550 m³/hr with 70% efficiency)

- Ventilation system to be fitted with controls with CO₂sensor

553.33

61.95

128.7

KITCHEN

20.0

(40.0)

1425

(2850)

Ventilation fan with flow rate of 1425 to 2850 m³/hr with variable speed is recommended.

(Cost and energy use is calculated based on fan with 1650 m³/hr flow rate)

350.00

187.2

DRYING ROOM

2.2

156.8

Ventilation fan with flow rate of 156.8 m³/hr or more with heat recovery is recommended. (Cost and energy use is calculated based on fan with maximum flow rate of 220 m³/hr with 75% efficiency)

- Ventilation system to be fitted with controls with humidity sensor

290.06

30.45

811.2

Note:

^a Calculated based on minimum required fresh air rate of 5 litres/second per occupant and (based on recommended 8 l/s per occupant).

^b The investment and averaged energy use per annum is calculated based on information obtained through ventilation system supplier’s website that best met the required ventilation rate.

4. Conclusions

In this report a large number of solutions are identified and evaluated which can contribute to reduced energy costs, reduced carbon emissions and an improved thermal comfort of construction villages.

The solutions are listed in such a way which makes them readily adaptable by companies. Thus, the result tables of our demand side study will assist in selecting appropriate measures depending on the target energy savings and the available budget of the company.

The identified solutions can be applied to an existing construction site e.g. Laing O’Rourke’s Xscape site and the energy demand and environmental comfort can be simulated with the help of ESP-r. This way, interactions such as the influence of reduced lighting on the heating demand can be assessed. This has been done in the following step of our project.

Dry resultant temperature

Illuminance

Fresh air rate per person

Wall

Floor

Roof

Door

Window

Wall

Floor

Roof

Door

Window

INSULATION

OTHER BENEFITS

INTERNAL LIGHTING

HEATING