|
|
|
Key project outcomes |
|
|
|
Financial | |
|
||
| • | Cost savings (Year 1): £76,547 | |
|
||
| • | Payback time: 10 months | |
|
|
|
| Technical | |
|
|
| • | Electricity savings: 15.0% |
|
|
| • | Improved power quality |
| Environmental | ||
|
||
| • | CO2 emissions reduction: 334 tonnes (Year 1) |
|
|
|
|
| Summary |
|
| The Link Centre is a large leisure complex, comprising of an international-sized ice skating rink, swimming pool, indoor courts, climbing walls, a fitness studio and the local library. |
|
| Voltage optimisation was installed as one of a number of energy efficiency measures across the site. |
|
| Summary |
|
| The Link Centre is a large leisure complex, comprising of an international-sized ice skating rink, swimming pool, indoor courts, climbing walls, a fitness studio and the local library. |
|
| Voltage optimisation was installed as one of a number of energy efficiency measures across the site. |
|
| Background |
|
| The Link Centre is a large leisure complex, comprising an International-sized ice skating rink, swimming pool, indoor courts, climbing walls, a fitness studio and the local library. The site operates seven days a week for fifty-one weeks per year. The demand onsite would normally run anywhere between 400kVA and the maximum demand of approximately 750kVA, with the overnight baseload being approximately 300kVA. |
|
| Onsite voltages (Diagram 1) were high, peaking at just under 247V (Phase to Neutral). The whole site is fed by a single substation 1000kVA transformer. The Client has already implemented a number of energy saving measures, for example fitting high frequency ballast lighting and variable speed drives to some of their larger motors. |
| Installation |
|
| Installation was reasonably difficult with the main switch-room located in the basement plant room of the centre and existing equipment restricting access. An additional plinth as flood protection (Figure 1) was requested. The existing ACB main breaker was reused, reducing the overall cost of installation. Due to the limited access it was decided to install three single-phase units instead of a single three-phase unit. The model chosen, the PSR-16, was specified at 1441 Amps per phase and 318kVA at the 221V (P-N) set output voltage. An external by-pass switch was installed, allowing the Client full control over their supply. The specifications provided sufficient excess capacity for future growth of electricty use at the facility. |
|
|
| All preparations for installation were carried out beforehand, with the final connections made during a four-hour period on a Sunday evening to ensure minimum disruption. |
|
| Figure 1: Additional plinth supplied to reduce flood risk |
|
 |
| Measurement and verification |
|
| The regulator outputs were set to 221V (P-N) as the optimised setting, giving just in excess of 220V (P-N) at the furthest point on site as requested by the Client. |
|
| The initial survey projected a minimum saving of 14% of the overall consumption. The Client required us to prove these savings as confirmation of their own long term tests. It was decided to utilise the Regulator’s ability to adjust phase voltages whilst on-line and load. Medium and short term tests were be performed, in each case returning the site voltages back to near maximum and then reducing again to the optimised setting. Results from these tests combined with other test data allowed the actual savings to be calculated. The site voltages were increased to the maximum and allowed to run for a period. Then reduced to the optimised setting of 221V (P-N) within less than a minute and allowed to run for the same time period. The step change in voltage (all three phase voltages are summed and averaged for clarity) and the consumption are clearly visible (detailed graphs available on request). The results were analysed and comparisons made with the short-term tests. |
|
| Again, the site voltages were increased to maximum and allowed to run for a short period and then returned to the optimised value, this sequence was repeated on several occasions in short succession. The step changes in voltage (again all three phase voltages are summed and averaged for clarity) and consumption can be clearly defined. Analysed together with the previous results from the medium term test and other data, the calculated savings for this site will be approximately 15% of the usage, an increase over the previous estimate. |
| The voltage has been set at 221V, giving an incoming voltage of 220V (P-N) at the furthest point on site. Initial measurement and verification of site energy use shows that year-on-year electricity use has been reduced by 15.0% since the installation of voltage optimisation. |
|
| With a steady incoming voltage, electrical equipment will operate in a more benign electrical environment, thereby reducing maintenance requirements and extending the life of electrical equipment. |
|
| The electricity consumption of the Link Centre was 4,258,134kWh, which cost the Link Centre approximately £510,310. |
|
| The implementation of voltage optimisation has now reduced this to 3,619,414kWh (a saving of 638,720kWh) and a reduction in CO2 emissions of 334,050kg (calculated at 0.523kg CO2/kWh). |
|
| The cost savings of £76,547 per year will deliver a return on investment within less than 10 months. |
