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HEIF Science D retrofit

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HSU's Science D Building


Figure 1:Energy Consumption at HSU

The Sci D/E complex includes the science and engineering building as well as the greenhouse at Humboldt State University. The building (Sci D/E complex) was originally designed by Ratcliff Architects. Paul Wright and William Lowe were the contractors for the project. The idea was for a state of the art design, utilizing passive solar heating from the south and west facing windows and vents as a major architectural feature. As is common in the state building bidding process, the lowest bidder is awarded the project. Due to inflation and the time lapse in cost figuring, the contractor found the project funding to be insufficient, and the computer controllers for opening and closing solar heating and cooling vents were eliminated. The manual controls installed in place of the computers were ineffective. The building never cooled or heated properly, and the passive solar design proved to be a primarily inefficient. Several attempts at addressing these issues have been made since 1982. The current system of cooling and heating makes the Sci D/E complex one of the biggest energy users on campus as shown in Figure 1. The current proposal addresses these costs and plans.

Proposed Design Changes

Air Handling Fans located on roof of Sci D

In order to increase energy efficiency and lower CO2 emissions there are three major changes that the Sci D/E Retrofit proposes. Proposed changes include insulation of the hot water loop, conversion of the current pneumatic Sci D air and heat controls to Direct Digital Control (DDC), and the addition of Variable Frequency Drives (VFD) for Air Handling Fans. The combined changes are estimated to result in $22,000 to $27,000 in annual energy cost savings for HSU. The annual savings projections would allow for a payback period of approximately 2 years for all HSU-based funding.

Insulate Existing Hot Water Piping

Currently there is approximately 100 linear feet of uninsulated hot water piping that runs through Sci D/E. The uninsulated pipe creates an excess of cooling whenever the piping is heated. This unneeded heating of the surrounding return air is one example of energy being wasted. Insulating the current copper hot water distribution piping would result in savings in heating and cooling. The total amount of annual savings from heat lost, gas lost, and electricity lost is approximately $821 according to a 2005 Energy Audit by Urfer Engineering. The annual energy savings are estimated to be 3241 kWh. The budget to insulate the piping is $1500.

Convert Variable Air Volume Controls

Most of the pneumatic controllers that drive the air dampers in the Sci D vaiable air volume (VAV) terminal boxes are non-functional. Field operational checks have shown that because of this supply and return air fans have been operating at full capacity, "constant volume reheat mode", during occupied building hours since 2005 or earlier. The proposed design change involves converting pneumatic Sci D air and heat controls to direct digital control (DDC). By doing this the building will improve its air flow and thermal control as well as save an estimated $12,720 and 97858 kWh annually. This equates to a reduction of fan energy demand by about 60%. The budget to convert the terminal box and thermostat systems along with the remaining pneumatic systems to DDC is $46,500.

Install Variable Frequencey Drives

A variable frequency drive (VFD) is a system for controlling the output of an AC motor by limiting the amounts of electrical energy supplied. Installing these variable frequency drives on the Air Handling Fans is expected to have an energy savings of about 60%. This 60% comes from the replacement of the current Vari-cone flow control devices that are less efficient than modern VFDs.

Other Energy Saving Opportunities

Figure 2: Torn Diaphrams
  • The Air handling equipment is worn out in the Sci D/E complex. There are some torn diaphragms in the unit pictured in Figure 2, that are resulting in a loss of 1700cfm which is equal to a 12% system loss. The budget to repair these parts is $2,200.
  • The window tinting on the Trombe wall is degrading and peeling off in spots and should be replaced.


There are many potential benefits from Retrofitting the Science D/E Building that include,saving money on energy, lowering HSU's carbon footprint, maximizing energy efficiency, and many educational benefits for future engineering classes. There are several lower division and upper division Engineering classes that will be able to use the energy improvements as examples in their classes. The evaluation and monitoring done during the Retrofit provides useful data that can be used in several Engineering classes as either examples, or for students working on projects. The potential classes include ENGR 473, ENGR 471, ENGR 322, ENGR 326, and ENGR 331.


The total project budget is estimated to be $92,400. The overall request for Humboldt State University Energy Independece Fund (HEIF) is $25,000. In addition to money from HEIF this project is eligible for funding from the (UC/CSU/IOU) Energy Efficiency Partnership program (EEPP). EEPP will reimburse hsu $0.24/kWh or $1 per therm avoided in the first year up to 80% of the project costs. Multiple sources have estimated this funding to be equal to $42,400. 'Plant Operations has also agreed to provide $25,000 in matching funds.

Student Interns

There will be a variety of student opportunities that emerge from the Retrofit. Three 100 hour student internships will be appointed from a joint committee combined of stock holders in Plant Operations as well as HEIF. The interns will make about what the other student energy jobs on campus make in the range of ($10-12/hr). Each intern will have a unique set of job responsibilities and tasks expected of him/her. The Baseline Intern has duties that include installing energy monitoring equipment on SCI D/E fans as well as document steps taken during installation and baseline estimates. Some of the other duties include assisting in pipe insulation from ordering parts to installation. The intern will be able to gain additional on the job training opportunities in dealing with a retrofit project in a variety of ways, including working directly with Plant Operation personnel in RFP and funding applications. The Project Intern will serve as a liaison between the contractor and Plant Operations which includes training such areas as conducting meetings, field experience, and documenting the design and installation process. The intern will also present information obtained to the HSU community. The continuation of funding applications also runs through the Project Intern. The Verification Intern is involved in re-installing the energy monitor equipment and making a projection of the performance verification. They are then to Report results to the HSU Community and sponsors of the project. A finalization of all steps in the funding process and any issues that occur post-installation. In addition, all interns will work with Instructors from the Engineering Department to assure all data and procedures are carried out properly for accurate results. All Retrofit Data will be available to future 473 students and other classes. A student Intern will also be able to aid in all phases of the project.

Projected Timeline

The Science D/E Retrofit has been approved by HEIF for funding and the initial steps have begun. Plant Operations is currently in the process of acquiring a project contractor. The ideal start date was initially Fall 09’, however, a more realistic start date has been adjusted to Spring or Summer 10’. Despite the start date of the major improvements to energy efficiency the installation of energy monitoring readings has already begun. These initial readings play a crucial role in the data when compared to other data during different steps of the project. A detailed description of the retrofit timeline follows in appendix 6 on page 16 of the HEIF Proposal.

Recent Updates to Science D/E Complex

The 1990 chiller model was replaced in 2009 with a new unit as shown in Figure 3. Projected savings are 3200 kWh a year with a demand savings of 8kw.

Figure 3: Newly Installed Chiller Outside of Greenhouse

See Also


Direct Digital Control. (n.d.). In Wikipedia. Retrieved November 11, 2009, from

Tall Chief Comet. Personal Communication. October 27, 2009.

Variable Frequency Drives. November 9, 2008. In Wikipedia. Retrieved November 11, 2009, from

Robinson IV, J. Johnson, P. Kinser, B. Jacobson, A. Moxon, T. Brown, J.HVAC Efficiency Measures for Science D/E. Retrieved October 19, 2009 from