Overview

​

As one of the UK’s leading Housing Associations, Genesis (GHA) owns or manages around 33,000 homes across London and the east of England and their stock portfolio includes a range of properties - from temporary housing to rented homes for sale and supported housing.

Genesis is also part of the G15 group, which is made up of London's largest Housing Associations and are responsible for providing homes for around one in ten people living in the capital, working to address the chronic lack of housing by building new homes. Around 25% of all new homes that are under development in the capital are being built by G15 Housing Associations, including Genesis.

​

Challenge

​

Genesis approached Enerza Solutions to investigate and remedy a serious problem regarding various urgent issues on one of their major sites.

​

The site consists of 475 apartments over one 11 blocks ground level retail units and communal areas the site has a mix of social housing and private tenants.

​

The challenges faced were:

​

• To locate and remedy the riser bypasses in the DH system which were letting by, effectively causing the high return temps.

• Leaks in the district heating system causing pressure drop.

• No control over the plant room - all equipment set to manual running of internal and individual set points, strategy and optimisation were never considered or implemented and no duty cycling in place.

• A strategic maintenance regime required, to keep equipment running correctly, along with the recommissioning of existing dormant equipment.

• Ventilation intake needed redesign. The cold air intake was insufficient to run the gas turbine CHP units or provide for the 4 x 1.4 gas boilers.

• GHA were unable to bill tenants as the metering system data was unretrievable. 

• The MBUS System required redesign.

• Several issues with the HIUs in the apartments, such as failed valves, leaks, no HWS or heating in properties.

• Oversized boiler burners only allowed an excessive minimum of 420kw, therefore unable to hit the lower 200kw demand periods.

 

 The Enerza team addressed the following:
 

• Constant leak issues and plant room faults, which took it off-line every few days, not only causing high costs in maintenance & call outs but also high-cost of gas and electricity usage and many tenant complaints.

• Unnecessary high energy usage for the plant room.

• Tenant billing was estimated, causing high volumes of tenant complaints.

​

​

Solution

​

​

• Due to the number of rectifications on site, we needed to first look at solving the main issue of the plant room operations and get it running on a steady-state strategy. This required the complete rewriting of the BMS, to control a common, rather than individual, set-point, enabling the plant room to work as one unit instead of operating as individual pieces of equipment.

• Riser bypass valves were under-specified on the original install, causing the valves to fail in all risers, resulting in a constant flow on the return instead of regulating on temperature. These needed changing first, as this was having a masking effect on other potential issues downstream of the circuits.

• Remove old and fit new heat meters/electricity meters & water meters in all 475 apartments, which relay back on the WMBUS network via a fibre backbone to the main server where data is collated and stored for billing.                                                                 

• Whilst visiting the apartments for meter works, we also took the opportunity to service and repair defective HIU units.

• Completely redesign the ventilation to supply the correct air flow to all the equipment & integrate with the BMS system & interlocks.

• To re-establish communications and build a display/control dashboard on the Enerza BMS cloud system to allow for accurate display of data and historical logging, alarming and an easy-to-use graphical display for O&M purposes and reporting for GHA.

• The whole control strategy needed to be analysed & rewritten due to the lack of strategic control: The plant was previously set on more of a timed execution where all boilers would fire at high burn for ½ hour then switch off, causing a very inefficient control hysteresis, not to mention high running costs, this also caused massive temp fluctuations in the DH network.

• Fit a 500 kw fully modulating condensing boiler to cover the lower demand periods and use the existing boilers to hit high demand periods > 420k.

​

​

Operational Benefits

​

1. Total monitoring and control of the site to pinpoint alarms and site failures and achieve steady-state running and increase plant life expectancy. Reducing breakdowns by avoiding irregular running cycles (and consequent reduction ins call outs/breakdowns) and receiving alerts on a RAG alert methodology.

2. The client can visualise the site and any alarms and issues from anywhere, via email alarms, sent on activation. Reporting dashboards are also a very useful tool at the disposal of GHA.

3. Retrieval if meter readings and tenant billing resulting in income of around £1,800 per tenant, per annum, over 475 apartments, totalling 875k per annum.

4. Steady-state and modulating control of the plant room, resulting in a 85% reduction in reactive works/callouts to the plant room.

5. Temperature was stabilized and the DH network stopped leaking where joints were able to settles, saving cost by eliminating excavation works on the network.

6. All equipment is now duty cycled, increasing the life expectancy.

​

​

Cost Benefits

​

1. Provided an £875k annual income from tenant billing.

2. At least a 30% saving per annum on plant energy usage with the CHP dynamically satisfying base loads with boilers acting as backup to the CHP units a saving equating to 100k per annum.

3. A reduction in reactive O&M call outs of approximately £10£ to £20k pa.