The annual performance of the green hotel was monitored using flow and data logger meters on each technology and was assessed by comparing its water footprint and carbon footprint to a local Premier Inn hotel of the same size.
In the first year of opening, the green hotel has demonstrated significant carbon and water savings. This is a result both of the performance of the technologies but also of the team on-site, who have been trained to understand the technologies behind the design and to help with minimising everyday energy and water consumption, such as in washing, water usage, excessive heating or cooling.
The water footprint of the green hotel has been reduced by approximately 48%, due to water saving technologies and behaviours. With 18% of the water use of the hotel being delivered by the greywater recovery system, this means that the hotel has in fact only drawn 34% of the water from the mains that a standard hotel would have used, representing a 66% saving!
The carbon footprint is 81% smaller than the standard build hotel.
Tamworth Carbon Footprint 2009
Heat Pump
- 10.71%
Grey
Water - 0.55%
Lighting
- 2.68%
Mechanical - 2.32%
Solar
Pump - 0.14%
Ventilation - 2.26%
Energy
Saved - 81.35%
Thermal imaging of the hotel shows that the building is very efficient at retaining heat. Whiteness would indicate areas where the building heat is escaping.
The building has an energy performance certificate with an 'A' rating and we are awaiting a final BREEAM rating and we anticipate that this will be 'very good' or above.
From the range of technologies implemented at the Tamworth hotel, those that were most successful in terms of environmental and financial benefit were:
- Heat recovery from bathrooms.
- Rainwater/greywater recycling.
- Super insulated building and triple glazed windows.
- LED lighting and sustainable timber.
- Reduced cement/concrete.
Alternative initiatives to those implemented at the 'green hotel' are also under consideration. For example, the use of solar film as a more cost-effective alternative to solar shading. The use of solar panels to produce hot water has not proved to be very successful due to the fact that they generate most hot water between 11am to 3pm, but the peak demands of the hotel are 6am to 9am and 5pm to 8pm.
Whilst the ground source heat pump was expensive to install, it is believed that it would achieve a much earlier payback on larger hotels, with 100+ bedrooms.
Main technologies performance overview
Frame
The highly insulated frame and high performance windows have performed well for the first year and the building still looks as good as new.
Heat Pump
Overall energy has been monitored for the full year with detailed monitoring from May 2009 onwards. The summary shows an annual COP for the heat pump of 411%. Given the hot water load represents over 70% of the heat pump's workload, this is a really excellent result.
This is further improved by the solar hot water produced. From the initial setting up and optimisation of the GSHP, no gas has been used apart from during checking of the heat pump. An annual total heat delivered by the GSHP of 60,500 kWhrs or an average of only 5 hours per day for both compressors.
Solar
Although solar energy has only delivered 5,000 kWhrs for the year, a technical problem reduced the output. Since this was resolved better results have been observed.
We anticipate that next year will be closer to the predicted output of 12,000 kWhrs.
Ventilation
The heat recovery system has performed very well, the only issues arising have been related to the cleaning of the filters. Noise levels are very low and since final adjustments to fan speeds, no issues have arisen with temperature control either hot or cold.
LED Lighting
Power consumption, as expected, has been very low and failure rates have been below 3%. All failed bulbs have been replaced under warranty. Light levels are higher than a standard hotel and future schemes could use the same system with perhaps one third less of the fittings and with much simpler controls.
Water savings
After significant reworking of the greywater system we believe this is now working very efficiently with no freshwater supply being used for WC toilet flushes, only greywater which fully supports Whitbread water reduction strategy.
Water savings from aerated taps and shower heads have been very effective, saving approximately half the water compared to a standard hotel bathroom.
