• Passive solar design strategies, which combine basic energy efficiency practices with building designs that maximize natural heating,
• cooling, and daylighting; 
• Solar thermal systems for hot-water heating and ventilation air preheating; 
• Solar cells (photovoltaics or PV) for electricity generation; 
• Wind systems for water pumping and electricity generation; and
• Geothermal technologies for water and space heating. 

Passive solar design strategies include integrated building design techniques that reduce the need for mechanical heating, cooling, and daylighting. Techniques include passive solar heating, natural cooling and ventilation, thermal storage features, radiative and ground-coupling cooling, and the use of natural light (daylighting). Passive design also includes using roofing materials that reflect the sun’s thermal energy, such as light colored roofing shingles, tiles, coatings, and membranes. 

These techniques in a building design can yield considerable energy benefits, increase occupant comfort, and lead to substantial load reductions on the HVAC system. Passive solar design is best suited to new construction and major renovations because most components are integral elements of the building. Depending on site-specific conditions, a number of passive strategies can also be retrofit into existing buildings. 

Solar thermal systems include active and passive systems. Active solar water heaters use pumps to circulate water or some other fluid from the collectors, where it is heated by the sun and then sent to the storage tank, where the water remains until needed. 

Passive solar water heaters rely on gravity and do not use controls, pumps, sensors, or other mechanical parts; therefore, minimal maintenance is required during their lifetime. They are less expensive than active solar systems and can only be used in warm sun-belt climates. The roof structure must be able to support the load of the storage tanks. 

Solar cells or photovoltaic (PV) cells are devices that use semiconductor material to convert sunlight directly into electricity. Individual solar cells, most commonly squares of silicon, are wired together and laminated within a thin, protective glass case to make a module. In other cases, a very thin layer of noncrystalline silicon is coated on an inexpensive base. Though the thin-film material is less efficient at converting sunlight to electricity compared with other systems, its low cost and simplicity are compatible with certain applications. These modules can then be joined to form PV arrays. The amount of electricity generated by an array increases as more modules are added. PV systems range from very simple to complex. They also can be either remote or connected to the electric utility grid. In remote (or off-grid) applications, PV power is independent of existing utility lines and power grids. 

Wind systems use wind turbines to capture the wind’s power and convert it to usable energy using a rotor formed by two or three propeller-like blades attached to a central hub mounted on a shaft. This rotor assembly converts wind velocity to rotary motion. The rotating shaft turns a generator to convert mechanical energy to electrical energy. Wind turbines are typically mounted on towers at least 100 feet off the ground where wind is faster and less turbulent.

Wind applications may be either stand-alone or grid-connected. Stand-alone applications involve wind-generated power apart from utility lines and established power grids. The best opportunities for small wind turbines, which generate less than 50 kilowatts, are stand-alone applications in which grid power is more than 1 kilometer (0.6 mile) away. The turbines are designed for high reliability, minimum maintenance, and lower wind resources. Complete wind-power systems using batteries and modern power electronics can readily replace small diesel- and propane-powered generators. They can also be helpful in mitigating the cost of environmental compliance.

Geothermal technologies include geothermal heat pumps. A geothermal heat pump moves heat between a building and the ground. In the summer, a geothermal heat pump (GHP) operating in a cooling mode lowers indoor temperatures by transferring heat to the ground. The process can be reversed so that in the winter, a GHP extracts heat from the ground and transfers it to the building. Also, the GHP can use waste heat from summer air-conditioning to provide virtually free water heating. The energy value of the heat moved is typically more than three times the electricity used in the transfer process. GHPs are efficient and require no backup heat because the earth stays at a relatively moderate temperature throughout the year.

• Reduces energy use.
• Reduces pollution generated through traditional forms of energy production.
• Reduces costs associated with energy purchase.
• May increases occupant comfort by regulating temperatures more closely.

• Initial equipment costs may be high.
• Involves planning during design and construction stages of project.

Assumptions:

• Recurring costs include maintenance and capital replacement costs discounted over 20 years using the National Institute of Standards and Technology’s 1996 discount rate of 4.1%. 
• Energy costs are based on the U.S. Department of Energy’s projected energy prices for electricity in DOE Region 4. 

20-Year Life Cycle Cost Analysis

Note: This analysis includes a $1,500 per unit rebate from the Hawaiian Electric Company.  

Economic Analysis Summary 

• Simple Payback: 6 years
• Discounted Payback: 7 years

*There are multiple MSDSs for most NSNs.
The MSDS (if shown above) is only meant to serve as an example.

John Campos
Facilities Maintenance Division
COMNAV REG Hawaii
Navy Family Housing Office
988 Spence Street
Honolulu, HI  96818-3913
Phone:  (808) 474-1874
FAX:  (808) 474-1809

This is not meant to be a complete list, as there are other manufacturers of this type of equipment.