Riada represents several product lines that are well suited to high efficiency DES projects. These products can be applied at the main district energy plant, at the connections to each building, or within buildings in the district. All of these product lines will help maximize energy efficiency of the system.
Main District Energy Plant
Scotch marine boilers are a thing of the past with the modern AERCO Benchmark Platinum being the top choice for longevity, controls, and high seasonal efficiency.
Supplied in side-by-side pairs for a compact & efficient package of up to 3.5 MW / 12,000,000 BTU/hr condensing gas input in only a 6’x9’ footprint. The Edge controllers will communicate with each other for efficient boiler sequencing for plant sizes up to 28 MW / 96,000,000 BTU/hr. Low pressure drop, high turndown, O2 trim, advanced efficiency reporting, and long warranty are all features that make these boilers perfect for DES plants as a primary or backup heat source.
At False Creek NEU, SHARC Energy filtration skids are used with heat recovery chillers for an electrified district energy solution, recovering energy from wastewater that would otherwise be lost. SHARC recovery skids can also provide an ambient temp loop to a district, with heat pumps in each building rejecting or recovering energy using as needed. SHARC skids can be added in parallel to suit all sizes of district energy systems.
Likido R744/CO2 water-to-water heat pumps can provide decarbonized district loop heating energy with high temperatures. Variable speed reciprocating compressors offer high efficiency, the best longevity, and accurate temperature control with varying loads. Available in 4 & 6 cylinder models, these heat pumps can be applied to wastewater recovery applications alongside SHARC skids, seawater recovery with an external HX, ground source loops, or heat recovery applications.
Auxiliary Heat Sources
Hubbell CR electric resistance boilers up to 3.2 MW skids for electrified back up or top-up heat source. These units are meant for circulation applications and do not require a tank, which is great for standby loss savings. Modulating electric input means they will only use the energy required to meet the outlet temperature setpoint.
Naked Energy solar thermal collectors can inject solar heat into the DES loop when solar energy is available, reducing the load on the main plant. Evacuated tube collectors are the most efficient in cold climates as they are vacuum insulated and will not lose heat to the environment on cold days. Solar thermal can be useful to recharge geo fields on an annual basis for district systems that use ground source heat pumps.
Alfa Laval has been operating in Canada for almost 130 years and is an industry leader in heat exchanger technology. Their latest plate & frame heat exchanger designs have numerous efficiency-optimizing features for all applications and are designed to be easily serviceable in the field.
Balancing & Control
Each building on a district energy system has piping connections to the main heat exchanger with components to control & balance flow to that building. For best practice, pressure independent control valves should be used at each building. Using the Griswold MVP pressure independent control valve at each building node will ensure proper valve authority and prevent actuator ‘hunting’ with varying pressures in the system. With the MVP valve there is no external balancing valves required, and there’s no need for a one-third/two-thirds valve arrangement.
When flow & energy needs to be metered in DES or any HVAC application, ONICON is the clear choice for accuracy, support, value, and range of product technologies. The most robust & accurate choice being the F-3200 inline electromagnetic flow meter. Riada can assist in selecting the right metering technology for your district loop application.
Buildings in the District
For maximum efficiency of the main energy plant, many DES utilities will have a maximum allowable return water temperature for each building in the district. This means careful attention is needed to design the equipment downstream of the HX that is utilizing this energy. Specifically, the domestic water heaters and terminal heating units.
The PVI EZ-Plate Storage water heater can be applied in several configurations for use on district energy systems depending on project requirements. These water heaters are perfect for DES with their packaged high-efficiency plate heat exchangers, and built-in control strategies to guarantee low return water temps to the district loop even as DHWT’s get close to setpoint. The packaged digital controller on the tank controls flow on both sides of the HX to maintain hot water setpoint in the tank & minimize return water temperature to the district.
Radiant heat is ideal for efficiency, especially using low flows & low water temperatures to ensure the lowest possible return temperature to the district.
Runtal Radiators use flattened water tubes so water flow can never go laminar, allowing low flow rates with high delta-T on the heating system. Shown here in the lobby of the UBC Campus Energy Centre.
Twa Ceiling Panels can be provided with high surface area in the space for maximum delta-T of the heating water temperature, as shown here in heating & cooling application at MEC Head Office.