Case Study: UPS Power Protection for Community Housing Association's Server Room

The SRE power projects team were tasked with finding a way to protect the server room at a housing association from long duration power outages.

The Power Problem

The server room currently has three server racks, each protected by APC 5kVA UPS. Their batteries are nearing their end of life and rather than look at replacement, the organisation wanted to consider a new centralised uninterruptible power supply. As well as being easier to manage, a new single UPS system would be installed with a new battery set and warranty. The new system would also be more energy efficient, with reduced energy usage, heat load and cost of ownership.

Site Challenges

The organisation provides support and services to a range of clients and is dependent on its IT operation. Due to its location, the site cannot use standby power generators and any UPS system installed in the server room must support both the IT loads and the local air conditioning system.

The server room uses wall mounted split air conditioning units and external condensers for cooling. With no onsite temporary power generation, the air conditioners cut out during a power outage. Without cooling, the IT network housed in the server racks and supporting the organisation, continues to generate heat. Room temperature rises quickly, with the potential for equipment damage and shutdown.

A long runtime uninterruptible power supply was required to provide up to 8hours runtime. The UPS had to power both the server rack loads and local air conditioning. The UPS battery pack also had to be larger enough to provide up to 8 hours of runtime, to protect the server room from long duration power cuts, both planned and intermittent.

The server room floor is solid and there is no raised access floor. This means that all power and network cable routes are top-down, through the ceiling void.

The UPS Solution

A CertaUPS C750 20kVA uninterruptible power supply was selected. The CertaUPS C750 range consists of 10 and 20kVA models and can be installed as a single-phase output (1/1 or 3/1) configuration or as a 3phase UPS (3/1). The chosen configuration as single phase UPS (1/1) and a suitable UPS maintenance bypass was installed with its output supplying a sub-distribution board to which the server racks and air conditioning system were connected. The battery pack is based on 10-year design life Yuasa SWL batteries with temperature monitoring installed.

Overhead cable runs were managed to the UPS bypass arrangement via a specially constructed cable tray. This ran up the battery cabinet and within the ceiling void, helping to support the weight of the power cable.

For remote monitoring, the CertaUPS was installed with an SNMP interface card. This give allows the UPS to be given an IP address on the local IT network for browser monitoring and SNMP communications. CertaUPS software also provides automatic reporting and controlled server shutdown if a mains power outage were to outlast the batteries.