To evaluate the energy saving potential of the flow-demand-based control, a simulation-based case study is conducted by applying the flow-demand-based control and the conventional fixed-DP control (to maintain a constant DP across the supply and return mains
), respectively, to a real distributed GSHP system.
(100 mm) supply and return mains
from Science Center to Academic Center (850 ft [259 m] total) were estimated to cost $53,600; and
Ductwork may also benefit from an Internal fiberglass lining (which serves as thermal insulation and absorbs sound) or a canvas collar between the equipment and the supply and return mains
, which would limit vibrations that resonate through the duct, says Tony Mori, senior HVAC estimator and planner for Crockett Facilities Services.
RJN will evaluate the feasibility of combining these pipes together into a single sewer main, which would cross State Highway 303 and several 12-inch high pressure gas and salt water return mains
. A capacity analysis will be performed.
The project's highlights include a more than 70km long treated sewage effluent return mains
, a deep terminal pump station of approximately 60m, advanced sewage treatment works with an initial capacity of 500mn liters per day, a conveyance system consisting of over 30km of deep main trunk sewerage and 70km of lateral interceptor sewers.
With roof-mounted boilers, the water supply and return mains
could be run inside the warm buildings to manifolds mounted at the street level.
Thus, the value of end loops is quite significant during a main pipeline failure as they help with flow redistribution to the open supply and/or return mains
. A hydraulic analysis provides a more quantitative understanding of this value of end loops in mitigating flow imbalances in different failure scenarios.
In July's "Big Plant in a Small Space" by Blake Ellis, in Figure 4 the chilled water expansion tanks (and makeup) are shown connected to the upper and lower return mains
. I am wondering if there should also have been a makeup and expansion tank connection to the "headered" loop, which facilitates the use of any pump to serve any chiller.
Control is entirely governed by the pressure difference between the supply and return mains