Comcast contracted Hitachi Consulting to explore energy conservation measures (ECMs) at five headend sites in the West Division and five in the Central Division. The task involved an on-site energy assessment, development of computational fluid dynamic (CFD) models of existing airflow conditions, and recommendations of ECMs for each headend. The effort resulted in identification of three key measures that apply broadly to Comcast headends and hubs: airflow optimization, advanced HVAC controls, and replacement of older, less efficient and ozone-depleting refrigerants. Implementing these three measures would provide a 5-year energy savings opportunity for the ten sites of just over $1.5 million, with the annual savings being just over $300,000. Hitachi Consulting also assessed LED lighting opportunities at the ten headends. Implementation of LED lighting and controls would provide a 5-year energy savings opportunity for the ten sites of just over $300,000, with the annual savings being just over $60,000.
The motivation for the effort is the fact that cable headends and hubs often do not employ the most modern cooling practices such as contained equipment aisles with hot/cold aisle discipline, which is now common in most data centers. These headends and hubs consequently have far more cooling capacity that would otherwise be needed. The challenge is to explore what could cost-effectively be done in these facilities to achieve significant energy savings in a reasonable payback period.
Detailed cost proposals from a multitude of subcontractors across all sites was not feasible for the present effort. However initial estimates indicate that payback periods on the order of 3 years or under are feasible for most sites and with sites in states with higher utility rates paying back even sooner. The estimated range of implementation costs varies from approximately $40k to $160k, depending mainly on the size of the site. The true cost of implementation and payback period can only be determined from piloting the ECM implementations and measuring the actual energy savings obtained in the pilots.
In addition to potential energy consumption and cost savings benefits, there are also significant performance and customer satisfaction improvements that come from having more efficient, robust, and redundant cooling in headends and hubs. The benefits of the airflow optimization, advanced HVAC controls and refrigerant replacement also improves:
All of this leads to significant operating expense (OpEx) cost reductions and improved customer satisfaction via reduced IT equipment downtime.
More optimized cooling technology can also reduce the cost of future capital investments by lowering the tonnage of cooling required in replacement projects. The reduction of total energy consumption at headends and hubs can also enable more sites to be viable for alternate energy projects that seek to reduce Comcast’s dependence on the electrical grid and reduce the carbon footprint overall.
The specific energy conservation measures recommended in this effort include:
Air Flow Optimization (AFO):
In this report, the results of detailed site visits, modeling and recommendations for each of the ten headend sites will be presented, followed by an analysis of the portfolio overall as well as conclusions and recommendations from the effort.
The ten Comcast headends covered by this report are:
West Division Sites
Central Division Sites
The potential energy savings associated with implementation of these three ECMs at the 10 headend facilities is summarized in Table 1 below. The average utility rate for these 10 sites was $0.081, and as stated in the introduction, when all sites are considered, the total energy cost savings over 5 years was estimated to be $1.5M.