How to save energy and reduce your heating bill
Transcript of How to save energy and reduce your heating bill
How to save energy and reduce your heating bill23 February 2016 | Hampden Park
Workshop aim
To provide you with the skills and tools to:
• Establish your own organisation’s heating
energy use
• Identify opportunities for improvement
• Build the business case for measures
Today’s agenda
09:15 Welcome & drivers for resource efficiency
09:35 Understanding your current energy usefor space heating Exercise 1 and Q & A
10:35 Thermal Efficiency
11:10 Networking Break / Meet Suppliers
11:30 Heating distribution and control
11:50 Boiler replacement and fuel switchingExercise 2
12:30 Making a business case
12:35 Case study (Green Network for Businesses)
12:50 Q & A and Next Steps
13:00 Networking lunch + Museum Tour
Why resource efficiency?
What are resources?
Water Energy Raw Materials
A global downturn?
Oil Copper Cotton Soya
23% 68% 18% 16%
Global growth rates
Critical resources arerunning short
Silver <30 yearsIndium <10 years Zinc <40 years
• Landfill Tax Regulations 1996
─Currently £80/tonne
• Waste (Scotland) Regulations 2012
─paper, card, plastic, glass and metal
• Climate Change (Scotland) Act 2009
─80% reduction in GHG emissions by 2050
• CRC Energy Efficiency Scheme
• Climate Change Agreements (CCA)
Legal drivers
Growth that doesn’t cost the earth
Increasing energy prices and market
volatility
Rising material and waste costs
More demanding customers
Increased efficiency &
profits
Improved staff morale
+ recruitment
Green credentials + increased sales
Resource efficiency drivers
FINANCIAL PRESSURE
IMPROVED COMPETITIVENESS
Understanding your current energy usefor space heating
Types of heat
What is thermal comfort?
• Different for every person
─Air temperature
─Radiant temperature of surfaces
─Relative humidity
─Air movement
─Metabolic heat / Activity level
─Clothing
─Well being
What are sources of heating?
• People
• Thermal mass
• Insolation
• IT
• Cooling equipment
• Process equipment
• Heating system
Understanding the units
Electricity Example
A 1-bar electric fire has a
power rating of 1kW
Running for one hour
uses 1kWh
Assuming 13p per kWh
= 13p per hour
Gas Example
A 27kW domestic gas boiler
runs at a duty rate of 30% on
a cold evening so the average
power rating is 8.1kW
Running for one hour uses
8.1kWh
Assuming 4p per kWh
= 32p per hour
Energy is measured in kWh – kilowatt-hour
One kWh is one unit on an electricity or gas bill
A kilowatt-hour is the energy used by a 1000 watts appliance
running for an hour
What data should you collect?
• Record kWh and cost from each quarter or monthly bill
• Collect at least 1 year of data, preferably 3 years
• Estimate that around 10% of heating will be used for hot water
What about electric heating?
• Some buildings will use direct resistive heating either for direct panel heaters or air-conditioning units
• If you only have one electricity bill then you can make a quick estimate that 50% of electricity is used for heating and 50% is used for all other electricity needs
• Some electrically heated sites will have a separate circuit supply storage heaters on a cheaper rate.
Worked example
• Average gas cost for last 3 years is £6,300
– how many kWh of gas is being used if last billsays the unit rate is £0.04?
• Answer gas kWh = [gas cost £]/[unit cost in £/kWh]
= £6,300/£0.04
= 157,500 kWh
Worked example
• We know that 5 x 2kW electric bar fires are also being used as supplementary heating for 8 hours on 100 days per year.
• How much is this costing compared to the gas?The unit rate for electricity is £0.12/kWh
Answer: kWh of electricity = 10kW x 8 x 100 hours
= 8000kWh
Answer: Cost of electricity = 8000kWh x £0.12/kWh
= £960
Smart metering
• Smart metering is due for all SMEs between 2015 and 2020
• Many already have ‘Advanced Meters’ which provide daily or half-hourly data
• A smart metering trial found that giving organisations good data resulted in a 5% reduction with no other input (Carbon Trust Smart Metering Trial 2007)
Measuring and monitoring spreadsheet
Using graphs and charts
External factors
Identify other influences on your data:
• Cost
• Outside temperature or weather conditions e.g. degree days
(www.eci.ox.ac.uk/research/energy/degreedays.php#degreeday)
Benchmarking
• To allow comparison between buildings it is useful to compare kWh/m2/year (kilowatt-hours per square meter per year)
• So for a 20m x 50m factory = 1000m2
• Considering the previous example with 157,500kWh
• Consumption per m2 = 157,500/1000 = 157.5kWh/m2/year
Benchmarks for heating(CIBSE TM46)
Building type Fossil-thermal typical benchmark kWh/m2/year
General office 120
Large non food shop 170
Bar, pub 350
Hotel 330
Workshop 180
Fitness and Health Centre 440
Storage Facility 150
Use benchmarks to...
• Understand your current space heating costs
• Set targets for reduction
• Estimate savings potential
• Discuss options with senior management
• [Larger organisations should consider degree-day benchmarks]
Exercise 1
Exercise 1 (20 minutes)
You work for a small manufacturer. Your site has two buildings:an office heated with electric storage heaters; and a gas-heated engineering workshop.
You want to reduce your space heating bill. Based on the information below, which building would you say has the greatest savings potential?
Key information:
General office Heating Electricity cost Y1: £3,450Heating Electricity cost Y2: £3,250Heating Electricity cost Y3: £3,400
Unit cost: £0.08/kWhOffice size: 200m2
Workshop Gas cost Y1: £4,500Gas cost Y2: £4,900Gas cost Y3: £4,700
Unit cost: £0.04/kWhWorkshop size: 600m2
Helpful hints
• Step 1 – Find the average energy bill for the last 3 years
• Step 2 – Find the kWh usage
─ Either read from bill (data not presented in example) or calculate from cost
─ Energy [kWh]= Cost [£] / Unit cost [£/kWh]
─ Take off an estimated % for non-heating use.
• Step 3 – Find the kWh per square meter
─ Energy per square meter [kWh/m2] = Energy [kWh] / Area of premises [m2]
• Step 4 – Compare Energy per square meter with benchmarks
• Step 5 – What is your conclusion about where savings could be made?
• Step 1 – Find the average energy bill for the last 3 years─ Office 3 yr average = £3,367
─ Workshop 3 yr average = £4,700
• Step 2 – Find the kWh usage
─ Either read from bill (data not presented in example)or calculate from cost
─ Energy [kWh]= Cost [£] / Unit cost [£/kWh]• Office = 42,083.33 kWh
• Workshop = 117,500 kWh
─ Take off an estimated % for non-heating use. • Workshop reduced usage = 105,750 kWh
• Step 3 – Find the kWh per square meter
─ Energy per square meter [kWh/m2] = Energy [kWh] / Area of premises [m2]• Office = 210.42 kWh / m2
• Workshop = 176.25 kWh / m2
• Step 4 – Compare Energy per square meterwith benchmarks
Benchmark
(kWh / m2)
Our Site
(kWh / m2)
General office 120 210.4
Workshop 180 176.3
Thermal Efficiency
• Heat loss calculation
─ Boiler sizing
─ Back-up heating requirements
• Identify improvement opportunities
• Prioritise options
Quantitative understanding
• Roof
• Walls
• Floor
• Windows
• Doors
Fabric elements
Energy = Power x Time
Watt-hours = Watts x Hours
This is what we need to find out
• Measurement of the rate of heat transfer
• Standard values available to look-up
• Manufacturers / installers should be able to provide value
• U-Value = W / m2 / K:
/ square meters / KelvinWatts
U-Value
• Heat loss through walls
─ You have a solid walled building, with external wall area of 250m2.
─ You heat the building to 21oC and the average external temperature is 3oC
─ What is the heat loss through the walls?
Worked example
Heat Loss (Watts) = U-Value x Area x Δ T
250m2
21oC - 3
oC = 18
oC
Worked example
Heat Loss (Watts) = U-Value x Area x Δ T
250m2
21oC - 3
oC = 18
oC
2.1
Worked example
2.1 x 250m2
x 18oC = 9,450 Watts
9,450 ÷ 1,000 = 9.45kW
Worked example
A caveat!
These calculations are based purely on structural elements.
What else will impact on heat loss and energy demand?
Other factors
Ventilation heat loss
Hot water demand
Internal heat gains – power appliances (PC,
photocopier)
Internal heat gains – process
People
Lights
Solar gain
Boiler Efficiency
Rebound effects – the ‘Comfort Factor’
Improve the thermal performance of building fabric
• Loft insulation
• Under roof insulation
• Beware of asbestos
• Cavity wall insulation
• Check condition of wall for exposed locations
Improve the thermal performance of building fabric
Reduce uncontrolledair leakage
• Doors
• Windows
• Other draughts
• Check ventilation levels
are correct for current
activities
• Consider LEV (local
extract ventilation) for
dusty or fume filled
environments to
reduce heat losses
Reduce uncontrolledair leakage
Consider mechanicalheat recovery
• Air-to-Air heat exchangers can save up to
50% of heating consumption
Heating distributionand control
What do we mean by heat distribution?
• The system that delivers heat from sourceto point of use
• Usually ‘wet system’ with radiators
• Or air source heat pump
• Offers good potential for savings via improved controls
• Insulate pipework─ In plant rooms (easy fix velcro attachments
are available for awkward flanges and bends)
─ Consider insulating distribution pipework if itdoes not contribute useful heat
• Keep space around space heaters free─ Avoid files, desks and furniture up against heaters
─ Leave 15cm between radiators and furniture
• Record your heating system settings─ Use a simple record sheet to record date and change made─ Put dates in the diary (clock changes), Xmas holidays to change
settings as needed
Warm air distributionsystems
• May be HVAC system with gas boiler or ASHP
─Some HVAC systems can be adapted to make use of free cooling (cold outside air) and excess heat internal to the buildings (e.g. server rooms)
─Consult a specialist
• Consider VSDs (Variable Speed Drives) for HVAC and circulation pumps
• Ensure a dead band of 4 degrees C is set between heating and cooling
Typical heating controls
• Time clocks
• System thermostat
• Localised thermostats such as thermostatic radiator valves (TRVs)
• Zone controls (BEMS)
Types of time control
• Time clock
─Set start and finish times each day
• 7 day timer
─Set for earlier start on Monday morning
• Optimised heating controller
─Uses inside and outside temperature sensors
─Learns your building heat up time for different temperatures
─Switches on as late as possible
• Switch your heating off early
─Many buildings store heat effectively
─People and IT can maintain the buildingtemperature from mid-afternoon
─Try moving your switch off time back an hour
• Consider hot-desking
─Heat from occupants is concentrated in one area
─Switch off heating earlier in un-occupied areas
• Make sure colleagues understand controls
• Set appropriate temperatures
─Office / low activity 20°C
─Workshop / high activity 16-18°C
─Turning down setpoint by 1°C could save circa 8%
• Locate thermostats carefully
─Not near doors
─Not in sun
Control heat gains
• In shops
─Large heat gains from display lightingand refrigeration
• In offices
─From occupants and electrical equipment
• In factories
─From processes such as cooking, welding
• In many lightweight buildings
─Solar gains through thin walls and glazing
De-stratification fans
• Useful for high ceiling premises with a large variation in temperature with height and a reasonably well insulated and air tight building
• Interlocked heating controls
• Fast opening roller-shutter doors
• Air curtains
• Flexible doors
Boiler replacement and fuel switching
Boiler replacement and fuel switching
• Understanding boiler efficiency
• Knowing when to upgrade your boiler
• Fuel switching and Renewable Heat Incentive (RHI)
Boiler Efficiencies
• Many SMEs use smaller domestic style boilers
• Check your boiler’s efficiency at www.ncm-pcdb.org.uk
• All new boilers have to be A-rated (>90% efficient)
• Any boilers pre 1997 are likely to be inefficient –consider replacing
Condensing Boilers
• Have the highest efficiencies (>92%)
• Recover extra heat from flue gases
• Operate at lower flow temperatures (may need larger radiators)
• Need careful installation in order to make sure they can operate in condensing mode
• Need a condensate drain
Understanding boiler efficiency
• What do we mean by boiler efficiency?
(The % of input energy (fuel) that is
output as useful heat)
• What is a good/bad efficiency rating?
Knowing when toupgrade your boiler
• How efficient is my boiler?
• Age?
• Condition? Maintenance Costs?
• Specialist analysis
Fuel switching
• Consider switching if you are using a high
price fuel such as oil (but has reduced
recently), LPG or electricity (day tariff).
• Alternatives are
• Natural gas
• Biomass
• Heat Pumps – Air, Ground or Water –
source.
Biomass
• Burns wood in one of three forms
• Logs (Large scale, low fuel costs)
• Chips
• Pellets (Smaller scale, higher fuel
cost)
• High level of automation
• Very low carbon factor
• If sustainable fuel!
Biomass– free procurement guide
Heat Pumps
• Air Source – coefficient of performance (COP)of 2 to 3
• Ground Source – COP of 3 to 5
• Move heat rather than
create it
Renewable Heat Incentive
• Government funded subsidy for renewable
heat projects
• Paid quarterly per kWh of heat produced
• Rate fixed at commissioning and then paid
for 20 years (index linked)
• Helps pay for higher costs of renewable
equipment
• Typical paybacks around 8-12 years
Hotel:Oil to biomass conversion
Installation of biomass boiler without RHI:
Cost of system = £110,000 Fuel saving = £5380 (£14,620 oil - £9,240 wood pellets)Payback = 20 years (£110,000/£5,380)
Installation of biomass boiler with RHI:
Cost of system = £110,000 Fuel saving = £5380 (£14,620 oil - £9,240 wood pellets)RHI (6.8p/kWh heat generated) = £11,615 (170,820 kWh X 6.8p)Payback period = 6.4 years (£110,000/(£5,380+£11,615)
Radiant Heat
• Heat surfaces not space
Exercise 2
Exercise 2 (15 minutes)
Your organisation has a gas boiler that was installed in 1990.
Your gas engineer estimates your boiler’s efficiency at 70%.
The engineer recommends upgrading to a gas condensing boiler with an efficiency of 92%, at a cost of £10k.
• How much energy and money would you save each year if you upgraded?
• How many years would it take to for the investment to be repaid?
Key information: Gas costs: £0.04/kWhCurrent annual gas consumption: 150,000 kWh
Exercise 2 – Helpful Hints
• Step 1 – Calculate current gas annual cost
─Annual cost [£] = Annual gas consumption [kWh] x Unit Cost [£/kWh]
• Step 2 – Calculate the current annual heating demand
─Annual heat demand = annual gas consumption [kWh] * Boiler Efficiency
• Step 3 – Calculate the new boiler consumption
─New Annual consumption [kWh] = Annual heat demand [kWh] / New Boiler Efficiency
• Step 4 Calculate the gas kWh saving, cost saving and payback
Exercise 2 - Answers
• Step 1 – Calculate current gas annual cost
─Annual cost [£] = Annual gas consumption [kWh] x Unit Cost [£/kWh]
£6000
• Step 2 – Calculate the current annual heating demand
─Annual heat demand = annual gas consumption [kWh] * Boiler Efficiency
105,000 kWh (so 45,000 kWh per annum is currently going up chimney!)
Exercise 2 - Answers
• Step 3 – Calculate the new boiler consumption
─New Annual consumption [kWh] = Annual heat demand [kWh] / New Boiler Efficiency
114,130 kWh
• Step 4 Calculate the gas kWh saving, cost saving and payback
35,870 kWh and £1,435 and 7 years
How much CO2?
Rule of thumb:
(see DECC carbon factors for exact conversion factors)
£100Saved on oil, gas or
electricity
500kg of CO2
0.5t of CO2
or~~
Making a business case
Two questions from your finance department/boss/MD:
1.How much is all this going to cost us?
2.When do we get our money back?
And the other questions they should be asking:
1. Any other H&S considerations
2. Any other benefits?
Building the business case
1. How much is all this going to cost us?
• Rough estimate – price books on the internet
• Resource Efficient Scotland or specialist survey
• Quotes from contractors or suppliers. Resource Efficient Scotland can help you to review quotes and any assumptions made
Building the business case
PAYBACK
INTERNAL RATE OF RETURN
NET PRESENT VALUE
2. When do we get our money back?
Building the business case
Building the business case: payback
Simple Payback Period:
• The amount of time in years that it takes for an investment to be repaid by the savings it achieves
• Ignores maintenance costs
• Ignores savings through improved longevity (as long as the payback period is less than the expected life of the equipment)
Building the business case: Net Present Value
Net Present Value:
• Better for large investment or longer term projects
• Sums the cash flows in each year
• Discounts the value of money in the future
Simple Payback =Period
Cost of measure
Savings achieved per annum
= X Years
Building the business case: payback
Building the business case: Net Present Value
• Useful for large investments and/or long payback periods
• Useful for comparing projects with different lifetimes
• Choose the number of years that you evaluate a project over
Year Cashflow YearDiscountedCashflow
Year 1 -6000 Year 1 -6000Year 2 1300 Year 2 1300
Year 3 1300 Year 3 1235Year 4 1300 Year 4 1173Year 5 1300 Year 5 1115
Year 6 1300 Year 6 1059Year 7 1300 Year 7 1006
Year 8 1300 Year 8 956
Year 9 1300 Year 9 908
NPV 2751
-£7,000
-£6,000
-£5,000
-£4,000
-£3,000
-£2,000
-£1,000
£-
£1,000
£2,000
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9
Discounted Cashflow
NPV
Building the business case: worked example
Existing New
Gas Cost £6,000 £4,250
Boiler Efficiency 70%(estimated)
92% quoted
Gas consumption 150,000 114,000
Heating Demand 105,000 105,000
Boiler cost £10,000
Gas unit cost £0.04 £0.04
SAVING £1440 + maintenance cost improvement
Simple Payback period 6.9 years
Replace gas boiler for a single-shift factory 50 wks/yr 5 days/wk
Improvement measure: Gas Boiler Replacement
• Rationale
• Description of the measure
• Costs including quotes
• Payback or NPV
• Any other benefits
• Any H&S considerations
Building the business case: summary
Get funding
• Advice and support on 0808 808 2268
• Free Guide ‘Sources of finance - How to fund your resource efficiency Projects’
• Upcoming webinar
Green Network for Businesses
• Opportunity to connect with a green business that has already implemented
• Help cut waste, water, energy and raw material costs
• More than 170 members
• Lead by example and showcase best practise
Green Network for Businesses
• Online search tool – find a business near you
• Read case studies and watch videos
• Book a visit
• Connect by phone/email
Heating –Member experiences
• Heat pumps, biomass and energy efficiency
• Range of sectors and locations
• Haldane – Fife─ Manufacturer of timber products
─ Lots of waste and a cold factory
─ Saving £4,000 per annum on energy bills
─ Saving £9,000 per annum on waste
─ RES SME loan
Heating –Member experiences
• Heather Hills Farm - Perth─ Freezing working conditions and rising energy bills
─ Polyurethane spray foam insulation
─ Double glazing
─ 18 KW wood-pellet boiler
• Film City – Glasgow─ Historic building, 25 tenants
─ 10 year energy bill predicted at £1million
─ Programme for Sustainability, ‘Green Wardens’
─ Mineral wool insulation
─ Insulating curtains
─ Zonal controls
─ Decrease in electricity usage, gas usage halved
Q&A and Next Steps
Q & A
Barriers to resource efficiency
Helping you overcome the barriers to resource efficiency
Helping you overcome the barriers to resource efficiency
Helping you overcome the barriers to resource efficiency
Helping you overcome the barriers to resource efficiency
Helping you overcome the barriers to resource efficiency
How much can you save?
£12,264 £15,992
£42,651
£26,788
£43,750
£39,183
£45,469
£60,930
<10 10 - 49 50 - 99 100 - 149 150 - 199 200 - 249 250 - 499 > 500
Average savings per business size
Number of employees
£19.5kAverage savings
per business
• Free online training for your environmental team
• Bite sized modules teach latest resource efficiency knowledge and practice
• Certificate on completion
• Ideal lunchtime learning
E-LEARNING Green Champions Training
'Great course for businesses that want to learn about resource efficiency at their own pace. I highly recommend this course”Seamus CorryAssistant Manager | Cloybank
The Resource Efficiency Pledge
Helping your business to plan, inspire and take action, so that you can reap the benefits of improved resource efficiency.
motivate your staff and senior management, and bolster their commitment to achieving your business’s environmental goals
focus your efforts on a clear set of achievable performance improvement actions
get the recognition you deserve from employees, customers and wider stakeholders
"By committing to a Resource Efficiency Pledge, we believe we will reduce our carbon emissions, costs and generally be a more sustainable
business.“ Richard Carr, | Webhelp UK
“The pledge will encourage us to keep our staff and clients engaged and inspire us to keep investigating best practice and new innovations.”
Sarah Potter | Film City Glasgow
How it works