Abstract

A preliminary study of the feasibility of using existing drinking water supply systems to provide hot water for heating purposes to a typical 140-home subdivision has been undertaken. This preliminary study has centered on (i) types of municipal water system designs and effects of system design upon heating use; (ii) methods of using low-to-moderate temperature water for heating purposes and possible institutional barriers; (iii) identification and description of a typical residential community suitable for hot water heating; (iv) evaluation of thermal losses in the uninsulated main distribution system from the main pumping station having assumed geothermal heating to the subdivision; (v) evaluation of thermal losses in the uninsulated street mains in the subdivision; (vi) estimation of size and cost of the pumping station main heat exchanger to supply geothermal energy to the drinking water; (vii) sizing of individual house heat exchangers; (viii) pumping and power requirements to supply the increased water flow rate through the subdivision street water distribution lines; and (ix) pumping and piping requirements to provide heating water flow from the street lines to a typical residence. From the results obtained thus far, it would appear that the use of existing uninsulated water supply systems will be advantageous more » in many communities having nearby low-to-moderate temperature geothermal resources. « le Document type: Report

Abstract

The System Assessment Capability (SAC) is a suite of interrelated computer codes that provides the capability to conduct large-scale environmental assessments on the Hanford Site. Developed by Pacific Northwest National Laboratory for the Department of Energy, SAC models the fate and transport of radioactive and chemical contaminants, starting with the inventory of those contaminants in waste sites, simulating transport through the environment, and continuing on through impacts to the environment and humans. Separate modules in the SAC address inventory, release from waste forms, water flow and mass transport in the vadose zone, water flow and mass transport in the groundwater, water flow and mass transport in the Columbia River, air transport, and human and ecological impacts. The SAC supports deterministic analyses as well as stochastic analyses using a Monte Carlo approach, enabling SAC users to examine the effect of uncertainties in a number of key parameters. The initial assessment performed with the SAC software identified a number of areas where both the software and the analysis approach could be improved. Since that time the following six major software upgrades have been made: (1) An air pathway model was added to support all-pathway analyses. (2) Models for releases from glass waste more » forms, buried graphite reactor cores, and buried naval reactor compartments were added. (3) An air-water dual-phase model was added to more accurately track the movement of volatile contaminants in the vadose zone. (4) The ability to run analyses was extended from 1,000 years to 10,000 years or longer after site closure. (5) The vadose zone flow and transport model was upgraded to support two-dimensional or three-dimensional analyses. (6) The ecological model and human risk models were upgraded so the concentrations of contaminants in food products consumed by humans are produced by the ecological model. This report documents the functions in the SAC software and provides a number of example applications for Hanford problems. References to theory documents and user guides are provided as well as links to a number of published data sets that support running analyses of interest to Hanford cleanup efforts. « le Document type: Report