OCETA ENVIRONMENTAL TECHNOLOGY PROFILES
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DHS-1000 HYDRONIC-ELECTRIC DUAL HEATING
SYSTEM
CAT. #03-020 / 08-017 |
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PROCESS/ PRODUCT DESCRIPTION:
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Sustainable Environmental Solutions has developed the DHS-1000, a unique Dual Heating System that allows an electrically heated building to utilize its natural gas-heated domestic hot water system to offset the building's electric heating requirements. By routing available hot water to hydronic radiant baseboard panels situated in a given space or room, the DHS-1000 can displace over 50% of the traditional perimeter heating provided by electric heaters. Figure 1 shows the hydronic radiator panels used in DHS-1000 installations. Temperature in each individual room is controlled by a solid-state thermostat to ensure accurate temperature control. | 
Figure 1: Hot Water Baseboard Radiant Heating |
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Sustainable Environmental Solutions' proprietary Dual Heat control strategy is programmed into the building automation system. It monitors boiler operation and regulates circulation pumps to ensure that the potable hot water function of the original heat source is not compromised. The DHS-1000 system is able to generate a five to eight-year | return on investment depending on the age of the building and its current electric heating load per suite. For additional security of supply all the systems equipment can be connected to the on-site emergency generator to provide partial heating during power outages. | |
| PROCESS/ PRODUCT APPLICATION: multi-residential buildings residences Buildings Partnership |
The
DHS-1000 is best suited to electrically heated multi-residential
buildings that cannot be converted to natural gas heat due to high
installation costs and/or safety concerns. The DHS-1000 system is
relatively inexpensive and easy to install and does not require tenants
to move out or to remove or relocate furniture to accommodate retrofit
of the slim and unobtrusive heating panels. Most of the system is
prefabricated to the size required for each suite allowing for quick
installation. The first full-scale system was installed at a Seniors Apartment building in Oshawa, Ontario, in the fall of 1998. The 10-storey, 89-suite building has room-by-room electric baseboard heating and central gas-fired domestic hot water heating via two boilers mounted on the roof. Sixty of the Oshawa building's 89 units were retrofitted with the DHS-1000 system. The installed capacity in each suite was 1 kw (3416 BTU), and the electric heating system was left to operate under the control of a new high precision thermostat. The project was managed by Ontario Hydro as part of the Custom Solutions Program. Canada Mortgage and Housing and Ontario Hydro jointly supported the |
monitoring
of the building energy use during the first year of operation of the
system. The Oshawa seniors dual heating system operated trouble-free
the entire heating season, and tenants are pleased with the performance
and improved comfort level. Until the end of March, 1999, the
electricity consumption related to space heating decreased by about
90,000 kWh. Assuming a conversion efficiency from gas to heat energy of
60%, the corresponding gas consumption for electricity replacement
produced the equivalent to 90,200 kWh. The total amount of energy
consumed for space heating, taking into account the difference in
degree-days of heating this season was about 30,000 kWh, or 4.4 % lower
than previous years. The savings are attributed to improved performance
controls that reduced overheating and the need to open windows. The
savings in fuel costs (replacement and reduction) until the end of
March totaled $150 per suite. It is projected that for an entire
heating season, the savings will be $200 per suite, or a $12,000
reduction on a total energy bill of $130,000. Figures 2 and 3 present
the relationship between monthly electricity use vs. degree-days and
monthly gas use vs. degree-days based on the two previous heating
seasons. |
The data points on each graph are the five fuel bills corresponding to the period of operation of the Dual Heating system, while the straight line represents the baseline. The lower electricity consumption (Figure 2) and the higher natural gas consumption (Figure 3) are clearly evident. These results are consistent with results from the first pilot system installed in one suite in the same building in the fall of 1996. Significant savings were also produced in another pilot test in Ottawa where both the living room / dining room area and the bedrooms of the superintendent's suite were retrofitted. In addition to apartment buildings, Dual Heating systems can be economically installed in single family residences such as townhouses where the gas fired hot water tank can provide hot water to baseboard radiant panels installed throughout the townhouse. The first four units of a 24 unit townhouse complex in Oshawa is now completed and the potential to expand it to the remaining 20 units is under consideration pending a review of savings this winter. In the individual townhouse units a fully programmable thermostat controller is used to ensure the integrated operation of both the hydronic and electric heating systems. |
Figure 2: Monthly kWh vs. Degree-Days |
Figure 3: Monthly Gas Usage vs. Degree-Days |
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PROCESS/ PRODUCT OPERATION:
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The DHS-1000 system in a multi-residential building is supplied with hot water by the central gas fired domestic hot water system. The system is operated by activating and deactivating small circulation pumps that draw water from the domestic hot water riser so that it can be circulated through the hydronic heating panel before being returned to the riser. The pumps are controlled by the building automation control system, which is programmed to ensure that the demand for potable hot water is always met first. Figure 4 below shows the monitoring screen for the Energy | Management System. It reflects the control points and shows the logic of adjusting the running time of the pumps in response to the outside temperature. Domestic hot water supply return and tank temperatures are monitored to ensure its priority. The heating panels are slim line aluminum hydronic radiators (7 1/8" high and 1 1/16" deep), coated with high impact enamel for durability and pleasing appearance. The radiant heat is distributed evenly throughout the room and into neighbouring rooms, offsetting the heating | requirements from the electric heating system. The heating panels come in varying lengths allowing them to be sized to provide the required BTUs/hr based on the hot water input temperature and pump flow available. The radiant heating is found to be more efficient and comfortable than the hotter forced air and convection delivery methods. The heat generated by radiation does not create air currents for dust and pollen to travel on, thus providing a major benefit for allergy sufferers. |
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 Figure
4: Energy Management System - Monitoring ScreenClick HERE to view. |
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| VENDOR INFORMATION: |
Sustainable Environmental Solutions provides energy management products and services to multi-residential, commercial, and industrial facilities. Sustainable Environmental Solutions is a subsidiary of Sustainable Resources | Management (SRM), a resource management company that provides its services through a network of energy management consultants, including former utility and government experts. Sustainable Resources | Management retains membership in a number of trade and property management associations and recently has been qualified as an Energy Management Firm for the Toronto Better Buildings Partnership. |
This document was originally published February, 2000. It is best viewed with the font Times, size 12. While OCETA has reviewed this product/process with the Vendor and conducted limited independent investigation, OCETA assumes no responsibility for the accuracy and completeness of the information. |
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