CHP System Solution

Published:  14 October, 2014

PWE takes a look at a CHP solution, which was installed at one of the UK’s largest water parks.

The 26 year old boilers at Sandcastle Water Park posed a number of risks to the day to day operation of the business. Energy costs had risen to over 40% of operating overheads in the last five years. The management needed to reduce energy consumption without limiting customer experience. In addition, the facility was approaching the limit of available mains power, thus impeding future growth.

The Problems

• On busy days boilers could not produce enough hot water to meet the demand.

• A boiler breakdown reduced air and water temperatures so much, that in the winter it could take up to 48 hours to recover.

• A boiler breakdown during the holiday periods would shut the water park resulting in significant loss of revenue.

The boilers were not the only issue. The investment in the water park and its new features were attracting more visitors but without the infrastructure to support the impact of the upgrades.

• The hot water storage tanks were unable to meet demand and not all visitors could have hot showers.

• If the Park had to operate on two boilers it could only sustain a few hours of use.

• Any serious failure of the existing plant boilers and associated pumps and pipework would close the park .

• Locating parts for old or obsolete plant was becoming more difficult for maintenance staff.

• Limited access to the plant room via a spiral staircase for personnel and a small access panel in the roof.

• If the existing plant did suffer serious failure, the logistical and structural issues meant a straight forward replacement could take up to five weeks.


A recommendation was made to replace the boiler plant and add a CHP unit to help reduce these risks. A Council report was completed and recommended: “That the boiler plant and Combined Heat and Power (CHP) Unit is purchased by the Council at a cost of £606,972 and met through Prudential Borrowing. The cost of the scheme will be paid back through savings on energy costs over a period of up to 10 years and recovered by the Council via reduced subsidy.”

The proposal formed part of a ‘spend-to-save initiative’ as the alternative option was to install new boilers, at a cost of £451,000, without delivering the same savings on day to day running of a CHP system.

The Solution

Preston Lee Chambers, working as the client’s consultant, chose the shentongroup 200 kWe Natural Gas Cento Indoor Acoustic unit. The thermal demand was carefully modelled to ensure heat output could be used.

shentongroup worked closely with Preston Lee Chambers throughout the design and selection process and made available a number of desktop study scenario’s using their ‘Power Therm Savings Calculator’, which included assessments of financial and carbon savings.

Including the initial cost and maintenance the return on investment is expected to be less than three years.

Output and resilience of boiler plant + CHP unit* :-

Existing boiler plant output = 2250kW

New boiler plant + CHP unit output = 2950kW

Existing boiler plant output with one = 1500kW

boiler failure

New boiler plant + CHP unit with one = 2411kW

boiler failure

* Source Exec Report from Blackpool Operating Board

A heat dump radiator was installed to permit electrical peak lopping, even when limited thermal demand was available. This allowed future-proofing of the incoming electrical supply, by giving the mains incomer 200kW of spare head room as a result of generating it on-site.

The narrow compact footprint of the Cento design allowed lifting through the limited space via the plant room roof. During installation modifications were made and bespoke hinges were fitted onto the CHP unit’s doors to allow optimum functionality in a limited space.

The selected machine is maintained on a shentongroup Infinium24 fixed price maintenance contract, which includes a lifetime warranty covering parts, consumables, call-outs, remote monitoring and technical support 24/7. This contract enables the client to place all maintenance risks with shentongroup, thus giving totally predictable maintenance costs.

In addition to the Combined Heat and Power unit, high efficiency condensing boilers and rapid recovery hot water storage cylinders were also specified. System back up was also factored in to provide flexibility and resilience via 5 boilers (4 running/1 standby) + CHP unit.

A pre-tender survey was essential to progress the layout of the boilerplant, roof access requirements and structural implications.

The installation had to be complete before the summer season therefore the programme required works to be carried out during winter shutdown, in order to limit the impact on the Waterpark’s clientele.

The job was completed and the CHP unit is now providing a large proportion of the total site demand per year, to offset grid electrical and thermal energy.

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