MIL-HDBK-1003/11
4.2.5 Power Sales Agreements. Power sales agreements made with utility
companies shall be in the "Surplus Sales" category wherein only the power
generated in excess of facility demand is sold to the utility. Design of
the facility and negotiation of the power sales agreement should reflect
Navy policy which is to reduce utility costs rather than to seek profits
from the private sector for cogenerating. Other arrangements are possible
where all the electric power generated is sold to the utility at a price
based on the utility's highest unit cost of generation and is purchased back
from the utility at a cost lower than that at which it was sold. These
types of arrangements should be explored for commercial ownership options as
covered in Section 2.
4.2.6 Site Adaptability. Building, site, and facility utility systems must
be compatible with adaptation required to accommodate cogeneration
equipment. Adequate space must be available. For large plants, a minimum
of 5,000 sq ft (465 sq m) to 7,000 sq ft (650 sq m) should be allocated in
preliminary planning stages.
4.2.7
Electric Utility Grid Interconnection.
4.2.7.1 United States Locations. The local utility must allow cogenerators
to interconnect with their supply grid.
4.2.7.2 Foreign Locations. Situations in foreign locations must be
determined individually. Where such interconnections are not allowed, it
may be possible to isolate various loads for a dedicated cogeneration
facility.
4.2.8 Grid Protection Requirements. Grid protection/interconnection
equipment and ownership requirements vary depending on the Power Sales
Agreement negotiated with the utility. The local utility should be
contacted very early in the design concept stage because requirements differ
significantly. Utility companies may provide assistance in planning
facilities.
4.3 Heat Recovery Applications. Heat recovery is the process of extracting
heat from the working medium or mediums, such as diesel engine exhaust
gases, and transferring this heat to a source of water, air, etc.
4.3.1 Sources of Waste Heat. Heat may be recovered from engine jacket and
lubricant cooling systems and from the exhaust gases. Table 6 indicates the
potential for product heat recovery from each source. Theoretically, all of
the jacket and lubricant cooling water heat can be recovered; practically in
most cases only about one-half will be reclaimed to provide useful work.
Although applications are limited, direct use of the exhaust gases for
product drying, etc., can increase overall efficiency about 12 percent.
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