Solar panels offer array of hope

Serving over a quarter of a million people in the communities of Harlow, Epping, Bishop’s Stortford, Loughton, Waltham Abbey, Great Dunmow, Hoddesdon and Broxbourne on the Essex/Hertfordshire borders, The Princess Alexandra Hospital is a large district hospital with five sites, operated by the Trust that bears its name, and offers a broad spectrum of services to local people, ranging from accident and emergency facilities to general surgery, and from orthopaedics to head, neck and eye care. The Princess Alexandra Hospital NHS Trust also offers outpatient and diagnostic services at the Herts and Essex Hospital in Bishop’s Stortford, St Margaret’s Hospital in Epping, the Tower Centre Clinic in Hoddesdon, and Rectory Lane in Loughton. Solar thermal collection panels were first installed at the Princess Alexandra site in 2006, with that project driven by the then energy manager within the hospital’s estates department, Andrew Bell. Six evacuated tube solar thermal collectors (or panels) were fitted that year to the roof of the “Oslo” plant room, which serves a number of office outbuildings (including the one housing the estates and capital department), in what the Trust’s current-day energy manager Bill Dickson describes as “an exercise undertaken to test the waters”. He takes up the story: “Those first panels for the site efficiently pre-heat hot water for tasks such as handwashing to seven outbuildings in all, and very quickly proved their worth. However, the original installation was quite small-scale and, having convinced Board-level personnel of the merits of solar thermal energy, my predecessor wanted to take things to the next stage.” Energy Fund grant Early in 2007 therefore, shortly before Bill Dickson took over as energy manager in August, Andrew Bell applied to the East of England Strategic Health Authority for a £399,000 grant from the Government’s Energy Fund to finance three proposed energy projects – the installation of a further 40 solar panels for two other, large buildings on the site, and two new, ultra efficient All Energy boilers for the Oslo plant room. The grant was approved late in 2007 and the installation of the new solar thermal collection system began in July 2008. Twenty of the panels, each featuring 30 glass vacuum tubes used to harness solar radiation, were fitted first to the flat roof on the hospital’s main building, with the energy collected set soon to be used, following final wiring and pipework, to pre-heat hot water for the adjoining Kent Wing. It contains the Princess Alexandra’s Accident and Emergency department, as well as a general, and a children’s ward. Bill Dickson elaborates: “Via a well orchestrated plan we successfully lifted all 20 panels and the accompanying thermal stores onto the flat roof of the main building over a six-hour period one weekend last July as the first element of the project. “We had to arrange closure of some local roads to enable the panels’ delivery, but generally the installation went without a hitch.” Craned onto sloping roof A further 20 solar thermal panels, manufactured by Focus Technology, were subsequently craned onto the sloping roof of the hospital’s Jenny Ackroyd Centre, a short distance from the main block, where the energy collected will, again, be used to pre-heat hot water, this time for five wards, incorporating a combination of adult and children’s beds. The installation of all the panels was undertaken by Hertford-headquartered Micro- Generation Systems, a specialist in the integration of micro-generation technologies, i.e. renewable energy technologies where energy is generated at source and used to power a local facility. Established just two and a half years ago, the company has, director Adrian Clayton, explained, undertaken a significant number of solar thermal panel installations at UK schools, and is now keen to target the NHS. The Princess Alexandra installation is the company’s first at an NHS hospital, and, Adrian Clayton hopes, will serve as an excellent exemplar of what can be achieved to cut a large healthcare facility’s energy costs using solar thermal collection equipment. Installing the extensive network of copper piping that connects the solar panels to the thermal stores, heat exchangers and pumps was, he told me, a complex task, but one undertaken successfully and, as a brief tour of the plant rooms showed, extremely professionally and neatly, by specialist engineer Alan Kimber. The two separate solar panel arrays, each installed at an optimal 30-35° angle on the respective roofs, will soon be ready to begin collecting solar radiation; all that currently remains of the commissioning process is some final wiring work and the system will be ready for action. Energy costs set to hit £1.5 m Bill Dickson acknowledges that the installation could not have come at a better time: “In recent years our overall energy budget has been set at around £1 million, but this year I believe our energy costs will spiral to around £1.5 million, simply because of the way energy prices have risen over the last 6-8 months,” he explains. “While it is difficult at this stage to quantify the level of savings we will achieve in terms of our gas usage, I expect them to be significant, and what has been particularly pleasing is that, thanks to the availability of money via the Government’s £100 million Energy Fund, the installation has not cost the Trust a penny.” Adrian Clayton went on to explain the basic workings of the solar thermal collection systems installed. He said: “Each panel comprises 30 glass tubes some 1.8 m long, each containing a vacuum. The vacuum tubes, which work on a similar principal to a Thermos flask, transfer the heat from the sun to a metal manifold, which runs the length of the array, through which a glycol-based heat transfer solution circulates.” The liquid’s primary function, he explains, is to transfer the collected heat very rapidly through the copper pipework (as the liquid’s temperature can reach 220°C), to a large thermal store. These large cylinders store the collected heat and in turn transfer it to the existing calorifiers via a heat exchanger. The system design complies with HTM04-01: “The control of Legionella, hygiene, ‘safe’ hot water, cold water and drinking water systems.” The water entering the boilers at this temperature means they have significantly less work to do to get the water to the 70°C temperature required by regulations to prevent any Legionella risk. Bill Dickson says: “The result should be that our boilers ‘fire up’ up to 50% less often, significantly reducing the gas consumption of the two buildings fitted with the solar panel arrays.”Adrian Clayton adds: “While it is too early to predict precise figures, I would expect that, particularly in the summer months, when the solar gain is at its highest, around 40-50% of the two buildings’ hot water requirements should be met via the solar thermal collection system.” Pride in the job MGS, and Bill Dickson’s team, are clearly extremely proud of this first NHS installation of a solar thermal collection system. Adrian Clayton took considerable delight in showing me the extremely precisely configured system of pipework, thermal stores, heat exchangers and the pumps required to circulate the glycol solution through the system in a loop, as well as the pipework that will then feed the hot water into the wards and other medical facilities below. He added: “Much of the copper pipework is 35 mm in diameter, a significantly larger size than might typically be used, principally because of the scale of the overall configuration. All the joints are also press-fitted rather than welded, which gives an excellent seal, speeds installation, and means that, in the unlikely event of a leak, any faulty joint should be easy to repair via a simple crimping process.” With NHS maintenance budgets tightening and plenty of work for the Princess Alexandra Trust’s 30-strong estates team to deal with day-to-day across the 14.5 hectare hospital site, any new plant with low maintenance requirements is, in Bill Dickson’s words, “a godsend”. Minimal maintenance Adrian Clayton explains that, apart from “generally keeping an eye” on the solar panels and their glass tubes, pipework, pumps and heat exchangers, the only significant maintenance the two solar panel arrays and accompanying infrastructure should require is a yearly check of the glycol solution’s composition, and a change of the liquid every 4-5 years. Bill Dickson says: “It has been immensely frustrating over the past year to see many of our wider energysaving efforts effectively wiped out by the savage rises we have seen in the cost of gas, energy and oil. It is particularly pleasing, therefore, to be commissioning the solar thermal energy system, which should hopefully bring us significant energy savings once fully operational, at a time when the entire estates department is under constant pressure to identify ways to reduce costs. We are delighted with the way the installation has gone and, even now, are looking at putting together a strong business case for further solar panels using Energy Fund grant finance next year. “I am particularly keen to install solar panels on the roof of the Derwent Block, a mental health facility on the site’s periphery, but I am sure there is plenty of potential for further panel fitting to additional buildings in the future.” Hospitals ‘slow to adopt’ Asked his view on why, with rising energy prices, more NHS hospitals have not followed the same solar thermal energy route, Adrian Clayton blames the “rather naive and blasé attitude we have had as a nation to energy policy in the past decade or so, seemingly believing that natural resources such as gas and oil would never run out”. He elaborates: “While quite a number of UK schools are now looking at solar thermal energy collection, in our experience, at least, hospitals have been significantly slower to adopt.” While acknowledging that much of the slow healthcare sector take-up to date is “probably simply due to budgetary constraints”, Adrian Clayton believes there has also been a “quite widespread misconception” that solar energy generation will never be truly effective in the UK, because we get insufficient sunlight. “In fact,” he says, “evacuated tube solar thermal collection relies not on direct sunlight, but on solar radiation, which is emitted on a constant basis and is quite capable of reaching the panels through the clouds even on an overcast day.” He explains that this means that, while there will always be “the odd day” when the temperature is perhaps at, or below freezing, that little energy is collected, generally, even during winter months, an effective solar thermal collection system will generate sufficient heat to enable effective pre-heating of water, albeit to slightly lower temperatures than at summer’s height. Grants available He adds: “With grants such as that from the Energy Fund available, hospitals that can put together a convincing business case now have a potential funding stream that can, as with this hospital, enable installation of a sophisticated, but simple to run and maintain solar thermal collection system which we would anticipate will typically bring payback within as little as 5-7 years, often at no, or just a minimal, initial outlay for the Trust. “We must all remember that our fosil fuel-based energy resources are finite, and the fact that the Government has now said it wants to see the UK achieve an 80% reduction in CO2 emissions by 2050. This is despite it doing very little in concrete terms to actively encourage public sector organisations to use renewables, or to incentivise large building contractors, for instance, to go down this route. Surely, against such a backdrop, harnessing what is effectively a free form of energy makes excellent practical, as well as environmental, sense?” Bill Dickson concluded our discussions by telling me the hospital’s estates department has already calculated that the two arrays of solar panelling will cut the hospital’s overall C02 emissions by 16 tonnes annually, and is optimistic that the installation will bring correspondingly impressive reductions in gas costs. He says: “We’re actually pretty proud of this initiative; we believe we’re the first NHS Trust in the UK with such a substantial solar thermal collection system installed, but are equally keen that other Trusts, who may be scratching their heads about how to cut their energy costs at a time when we are all under financial pressure, see what we’ve achieved and consider how they might follow suit.”