Sustainable Hotel Design Presentation 3 Supply Analysis Group 5

Previous Presentations 1 st presentation –Site analysis –Site Selection 2 nd presentation –Passive design –Demand reduction

Where We Are Now Site C Initial Building Design North 1 st level Ground level

Our Aims for This Presentation Supply analysis –Water –Electricity –Heat –Gas

Electricity Demand kWh per year Lighting40,880 Catering26,864 Ventilation5,840 Cooling2,336 Equipment5,840 Swimming pool17,520 GSHP30,000 Other5,840 Total135,120

Heat and Gas Demand Heat DemandkWh per year Space Heating186,880 Hot water70,080 Swimming pool35,040 Total292,000 Gas DemandkWh per year Catering46,720

The Result 62% less electrical energy than an average hotel 13% less combustion fuel than an average hotel

Water Storage l/day Cold water11,000 Hot water12,000 l/year Swimming pool225,000 (Full Capacity)

Water Supply Possible Supply Sources Stream Scottish Water Rainwater collection Greywater collection

Reclaimed Water Greywater Storage –Toilet flushing 3 days –Car washing Rainwater 20 days –Toilet flushing –Car washing –Plant watering –Laundry

Reclaimed Water Rainwater Yield = Collection Area x Average Annual Rainwater Yield x Run-off coefficient x fractional collector efficiency = 1530m^2 x mm x 0.8 x 0.8 = 2,230,422 litres/year = 6,111 litres/day Greywater Yield = bathroom use in morning x no. of people = 80 litres x 70 = 5,600 litres/day (full capacity)

Reclaimed Water Total Reclaimed Water = 11,711 litres 55 wcs –180 litres storage per wc/day = 9,900 litres

Supply Systems Power –Wind –Small scale hydro –Photovoltaics Heat –Ground source heat pumps –Solar thermal collectors Combined Heat and Power –Biomass

Justifying CHP Sustainable design- reduced emissions Matches hotel demand profile well Efficient + cost effective Secure and reliable supply

Justifying Biomass ‘Carbon Neutral’ Process Can be self sufficient or locally sourced Lesser transport requirements (compared against fossil fuels) Encouraged by government and council

Operation/installation Strategies Integration with other technologies: PV, Hydro, boiler. GSHP CHP Hydro Pool Boilers PVT

Economics Heat/Power ratio 4:1 1.5kg/kWh e Wood Chip market value £40/tonne Fuel price = 6.0p/kWh e O+M = 1.5p/kWh e Total Price =7.5p/kWh e

Power Requirements Electrical Demand- Limiting factor Power Req. = 55 MWh Operational period 8000 h/yr CHP size = 15kW e Price = £1275/kW Total = £19 125

Simple Price analysis Electricity produced = 55 MWh Value of electricity= £3500 Heat produced= 220 MWh Value of heat = £4000 Savings per annum = £3750 Cost of CHP = £19125 Payback period = 5.1 years

Renewable supply options for the hotel Wave and tidal energy Solar resource Wind resource Hydro resource Bruce Henry

Wave/Tidal Power Discount waves and tidal as: – The bay is sheltered, cost for cabling – Expensive – Unreliable –Industry is in its infancy

Comparison of devices kWh/m 2 /year Gives an idea of power size ratio £ per kWh/year Give an idea of instillation cost and payback period

Solar power Photovoltaic devices Insolation 2kWh/m²/day (efficiency of 18%) 130 kWh/m²/year Approx £900/m 2 £6.16 per kWh/year 25 years

α = 1/7 V mean =6.2ms -1 P mean =279.8W/m 2 P betz =165.1W/m 2 Total available to wind turbines = 1446kWh/m 2 per year Wind Resource

Vertical axis wind turbine Rating:6000W Frontal area = 5 x 3m 11,000 kWh per year (733kWh/m 2 ) Cost: £30,000 £2.72 per kWh for year

Ducted Wind Turbine Size of device with is 1.5m x 1m Hence for these devices (735.3 kWh/m 2 ) Power coefficients of about 0.3 have been achieved for a 0.5 meter diameter. Cost is approx £800 £1.08 per kWh/year

Horizontal Axis Wind Turbine 600 Watt wind turbine/generator £1,845 Diameter 2.55m Output 450kWh/m 2 Total 2300kWh – £0.80 per kWh per year 1500 Watt wind turbine/generator £3,655 Diameter 3.5m Output 769kWh/m 2 Total 7400kWh- £0.49 per kWh per year 6000 Watt wind turbine/generator £7,765 Diameter 5.5m Output 816kWh/m 2 Total 19400kWh- £0.40 per kWh per year Watt wind turbine/generator £14,900 Diameter 9m Output 762kWh/m 2 Total 48500kWh- £0.31 per kWh per year

Micro Hydro Water 800 times denser than air, Constant power source Single nozzle version for heads from 34 metres and power output of 8kW. Flow requirement 40 l/sec £20K estimated, 70MWh per year available £0.28 per kWh/year

Summary

Micro hydro will be used to meet as much of the supply demand as possible. (70MWh/year) Proven 1500w turbines will make up difference. (14.8MWh/year) Total cost of installation = £27.5K Batteries will be incorporated to store power from the turbines

Solar Thermal Heating NW Scotland - produce around 300kW.h per m² annually. Building orientation - little defect on output within 45 degrees of south. Optimum tilt 33 degrees, little defect 15 degrees either way (pitch of roof). Solar collectors cost from £300-£700 per m². 2-4m² typical domestic system costs around £3000 and delivers around 1000kW.h per year meeting around half hot water demand. Pumped indirect system would be the most effective to install and would prevent freezing. Could possibly be used for space heating, water heating and heating the swimming pool.

Solar Thermal Space Heating Solar Thermal Underfloor Heating Seasonal Performance: Summer around 4kWh/m² (daily average) Winter around 1kWh/m² (daily average) Space heating requires large collector areas to supply heat in winter when it is needed most. ( m² for hotel)

Used to preheat hot water for CHP, large collector area required to cope with high hot water demand Collector area required to be larger than half the swimming pool to heat it (would cost around £30k) Solar Thermal Water Heating

Ground Source Heat Pump A 20kW heat pump would be required to provide kWh per year Cost around £ Provides 1/3 of hotels heating Ground temperature relatively constant around 11°C (sea temperature varies °C annually). Efficiency drops when temperature drops in winter, when it is needed most.

Ground Source Heat Pump COP of 3 - needing around 7kW electrical input Underfloor heating gives a higher COP as it works at a lower temperature (30-35°C) however radiators (50°C )give individual occupant control in bedrooms. Space available around site to dig a trench to lay horizontal ground arrays (cheaper than a borehole). GSHP connected to either five 50m closed loop horizontal ground arrays or a 200m trench for a spiral horizontal array.

Heating Supply Conclusions Solar thermal heating - not cost effective, require large collector areas and expensive capital costs to meet kWh annual demand. GSHP – more financially viable for meeting heating demand. Require top up heating from CHP if radiators are to be used, resulting in a lower COP.

Meeting Demand Demand (kWh)Supply (kWh) ElectricalWind = Hydro = CHP = Total = Total = HeatingGSHP = CHP = Total = Total =

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