Case Study

gasnetworks.ie

‘A’ rated building with natural gas Low impact, low energy urban living

Modern technology and renewable energy resources are used to a premium in this development. A gas fired Combined Heat and Power (CHP) unit generates both heat and electricity simultaneously through the combustion of natural gas. The energy generated is used to meet the Part L requirements of each apartment and is also used to displace some of the electrical requirements from the grid, providing “free” electricity that is then used to power common areas.

This highly efficient, low impact and cost effective system is further complemented by the use of a mechanical ventilation heat recovery system. This helps the development’s excellent Building Energy Rating while supplying clean, fresh air at maintained temperatures. This balanced approach means a high BER rating and lower carbon emissions.

Payback on installation cost within 5 years Operating within a central plant room, this solution not only provides the Part L renewable energy contribution for the development, but it also dramatically increases energy efficiency. It reduces emissions at minimal running costs and produces non grid electricity for use in common areas. In a development of this size, the system installed actually ends up paying for itself within 5 years. St. Raphaela’s apartment

complex, a Shannon Homes

development, is designed for

clean efficient energy usage. It

is an impressive example of low

impact, low energy urban living.

100 apartments over two blocks, floor area 94,195 sq.ft. (8,751 sq.m).

A3

Overall efficiency of 93% giving 608KWh per month additional heat gain, average savings of €333 per month.

‘A’ rated building with natural gas

District Heating Systems using heat from CHP units is one of the most cost effective ways of cutting carbon emissions – reducing the carbon footprint of multi-occupancy dwellings.

Low aesthetic impact and space savingsA lot of careful thought and detailed planning goes into designing a development of this calibre. The contemporary clean look of this development is maintained with minimal impact on the development’s aesthetic. By installing a central plant system, there is no need for a boiler per apartment. No flues on the exterior wall of each unit mean cleaner lines too. A single gas pipe and two exhaust flues brings its own cost and space savings. Other benefits include:

Reduction in space allocation for equipment by 44% (no need for individual apartment boiler or storage cylinders)

Reduced infrastructure costs and installation timelines – no individual boiler feeds etc.

Reduced running costs from commercial utility energy rates

Meeting the building regulatory requirements of Part L:Part L requires 10kWh of thermal energy (per square metre floor area) be generated renewably for use in the building’s heating or hot water system. Alternatively 4kWh of electrical energy can be generated – or a mix of the two. By using two CHP units in this development, (each with an output of up to 14.8 kW of heat and 5.5kW of electricity), the entire 94,000 square foot (8,733 square metres) development exceeded the renewable energy requirement by using natural gas only.

Energy managementFrontline Energy, a professional energy consultancy services company, manage the energy billing system at St. Raphaela’s.

Managing over 1,000 properties in Dublin, a system like this makes our job a lot easier. Landlords like the efficiency of the system, they also like the savings achieved by producing “free” electricity for use in common areas.

Other systems available on the market are not as easy to optimise. We present monthly or quarterly proof of the energy efficiencies we achieve and resulting cost savings to landlords.

Tenants control the heat in their own apartment and can be sure of instant heat and hot water from a cost effective and energy efficient system.

‘A’ rated building with natural gas

How it worksThe CHP system installed here provides the Part L renewable energy contribution for this development. The CHP system (2 units used here) generates heat and hot water to over 100 apartments. All heat is captured and reused. The system generates electricity from natural gas and uses the exhaust gases to provide hot water to the buffer tanks.

Here, the 1,000kW boiler system is designed to modulate down from 1MW to 50kW during low demand periods resulting in dramatic energy efficiencies. Since its installation, the CHP units operate between 20 to 22 hours per day, supplying heat to buffer tanks that is then distributed to all apartments via the district heating scheme. Overall efficiency of 93% giving 608KWh per month additional heat gain, resulting in savings of €333 per month, compared to conventional plant rooms.

Modular CHP units are flexible in their configuration enabling the CHP unit to fit into spaces that would normally be considered as dead space.

CHP units used to get a lot of bad press. The issue was that often the systems installed were overspec’d, therefore inefficient. These units are modular – so you only have to install the size of unit required, safe in the knowledge that it can be upgraded if necessary.

The average monthly performance figures for each unit on this site are as follows:

Hours run per month 671 Hours

Electrical output per month 3,691 KWh

Heat output from CHP 8,484 KWh

Additional heat gain from condensers per month 608 KWh

Fuel input per month 13,759 KWh

Efficiency 93%

1 The estimated monthly savings per CHP unit is €333 per month, compared to boiler only, equaling total annualised savings (including maintenance costs) of €7,000 per annum.

2 The estimated annualised carbon savings are 9 tonnes of carbon per unit, 18 tonnes in total.

1Savings were based on an electrical tariff of 18.36c/kWh, a night electricity tariff of 9c/kWh, a gas tariff of 3.18c/kWh and an assumed boiler efficiency of 90%.

2Carbon savings were calculated using carbon emission factors of 205gCO2/kWh for gas and 530gCO2/kWh for electricity and an assumed boiler efficiency of 90%.

BenefitsCost effective

Wholesale gas rates are cheaper than domestic rates, particularly if run together with a Combined Heat and Power unit, the cost of heat can be much lower than that generated by domestic gas boilers.

Comfort and convenience

Hot water and heating is available instantly “on-demand.”

Safety

Boilers and other heat sources are kept in a dedicated plant room with appropriate supervision by an ESCo Company. Natural gas is installed only in the dedicated plant room which is fitted with gas detection safety equipment and an auto shut-off function for added safety.

No annual boiler maintenance fees

CENTRAL PLANT

36571/06/2015

Builder: Shannon Homes Laraghcon, Lucan, Co. Dublin 01 628 2238

Architect: MCORM Architects Adelaide Road, Dublin 01 478 8700

Consulting Engineers: McElligott Oak Road, Dublin 12 01 424 3014

Mechanical Contractor: M&P Mechanical Services Castlebellingham, Co. Louth 042 9379 090

District Energy Operator: Frontline Energy Grand Canal Street, Dublin 2 1850 676 676

CHP Supplier: Kinviro Ltd. Kilcoole, Co. Wicklow 01 556 3100

The contact details for Gas Networks Ireland are:

Networks Services Centre, St. Margaret’s Road, Finglas, Dublin 9.

Businesslink: 1850 411 511Site Drawings: plans@bge.ienetworksinfo@gasnetworks.ie @GasNetIRLgasnetworks.ie

This information is only a guideline to the different products available for use with natural gas in new development construction. Users should ensure that products are suitable for the specific circumstances in which they seek to apply them. Contact the supplier or manufacturer directly for specific information on building requirements and materials needed for installation. Professional advice specific to the project should always be sought. The current Irish Gas Standards and Technical Guidance Documents (Building Regulations) override all contents. Users should ensure they always have the most up to date information.

With economic and environmental sustainability at the core of our company ethos, the DHS system at St. Raphaela’s is an ideal site for Frontline Energy to take a central role in improving efficiencies and constantly driving value for our customers.

Dave Connelly, CEO Frontline Energy & Environmental

‘A’ rated building with natural gas