RÉCUPÉRATION DE CHALEUR DES EAUX DE DRAIN PROJETS COMMERCIAUX, INDUSTRIELS ET INSTITUTIONNELS RÉALISÉS
Les bâtiments commerciaux et institutionnels sont généralement caractérisés par une utilisation fréquente et à volume élevé d'eau chaude qui est littéralement déversée dans les égouts. Le ThermoDrain est conçu pour récupérer cette énergie gaspillée et la retransférer directement dans votre système de chauffage d'eau potable, réduisant ainsi considérablement les coûts associés au chauffage de l'eau chaude. Notre échangeur de chaleur à double paroi est homologué pour une utilisation avec de l'eau potable.
Engineering Division • US Commercial, Multi-Family & Industrial Systems
Commercial Drain-Water Heat Recovery (DWHR).
Engineering Specifications & System Integration.
In US commercial facilities, multi-family developments, and student dormitories with substantial domestic hot water (DHW) loads, thermal effluent represents an unmined, continuous energy source. ThermoDrain® falling-film counterflow heat exchangers passively capture sensible heat from greywater stacks to preheat incoming municipal cold makeup water prior to primary water heating. Operating with zero moving parts, zero electrical draw, and certified under CSA B55.1 / B55.2, ThermoDrain delivers rapid compliance margin for ASHRAE 90.1, IECC C404, and IRA Section 179D / 45L tax incentives.
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Energy Modeling Spreadsheet (.xlsx)
< 2.5 psi (17.2 kPa)
Potable Head Loss @ 2.5 gpm (CSA B55.1)
46.2% – 59.1%
Certified 4" Heat Exchanger Effectiveness (ε)
CSA B55.1 / B55.2
Vented Double-Wall Potable Isolation Certified
Sec. 179D / 45L
Directly Eligible for Federal Energy Deductions
Third-Party Testing & Verified Product Registration
Independently Tested to CSA B55.1 and CSA B55.2 Potable Safety Standards
All published ThermoDrain® thermal efficiency ratings and hydraulic pressure loss values are derived from accredited laboratory testing under CSA B55.1 and audited for double-wall vented potable separation under CSA B55.2. Official ratings are indexed on the federal Natural Resources Canada registry, providing verified empirical submittal data for DOE EnergyPlus and eQUEST building models.
Engineering Fundamentals
Thermodynamic Principles & Pressure Drop Control
Unlike active greywater systems that require holding tanks, electric pumps, filters, and chemical treatment, ThermoDrain relies strictly on annular gravity flow and conductive copper heat exchange:
Annular Falling-Film Dynamics (DWV Side)
Vertical drainage entering the copper cylinder forms a turbulent annular film approximately 0.04 to 0.06 in (1.0 to 1.5 mm) thick against the inner tube wall due to gravitational acceleration and surface tension.
- Zero DWV Head Loss: The interior core remains entirely open to atmospheric venting. It causes no backpressure and requires no cleanout bypass.
- High Convective Heat Transfer: High film shear velocity creates convective heat transfer coefficients ($h$) exceeding 1,200 W/m²·K.
- Self-Cleansing Velocity: Grease, soap scum, lint, and hair cannot bridge the open 4-inch core diameter, eliminating operational fouling.
Counterflow Coil Hydraulics (Potable Side)
Cold municipal water enters the bottom fitting and spirals upward through rectangular-profile copper coils mechanically wound under tension around the central drain tube.
- True Counterflow Profile: Maximizes the Log Mean Temperature Difference (LMTD) by exposing the coldest incoming makeup water to the exiting drainage film.
- Controlled Friction Loss: Cross-sectional coil area is hydro-formed to ensure total pressure drop remains ≤ 2.5 psi at 2.5 gpm, preserving system pressure to downstream fixtures.
- Vented Double-Wall Isolation (CSA B55.2): An atmospheric capillary relief pathway isolates the potable stream from sewage effluent under all operating and failure states.
Thermal Transfer Formulation (ε-NTU Method):
q = ṁ × c_p × (T_out - T_in) = ε × C_min × (T_drain,in - T_potable,in)
Where: ε = CSA B55.1 certified heat exchanger effectiveness (0.462 to 0.591 for 4" commercial series); C_min = Minimum fluid thermal capacity rate ($ṁ \cdot c_p$); T_drain,in = Typical effluent temp (100°F to 104°F); T_potable,in = Municipal water main supply temp (40°F to 55°F).
q = ṁ × c_p × (T_out - T_in) = ε × C_min × (T_drain,in - T_potable,in)
Where: ε = CSA B55.1 certified heat exchanger effectiveness (0.462 to 0.591 for 4" commercial series); C_min = Minimum fluid thermal capacity rate ($ṁ \cdot c_p$); T_drain,in = Typical effluent temp (100°F to 104°F); T_potable,in = Municipal water main supply temp (40°F to 55°F).
Energy Policy & Code Compliance
Integration with US Energy Standards & Tax Deductions
DWHR provides a cost-effective path to meet stringent efficiency targets without altering exterior envelope thickness or glazing ratios:
ASHRAE 90.1 & IECC Section C404
Directly contributes to Service Water Heating (SWH) performance pathways. In high-density residential and hospitality projects, DWHR offsets primary water heating energy by 25% to 40%, generating substantial compliance margin against ASHRAE 90.1 Energy Cost Budget (ECB) baselines.
IRA Section 179D Commercial Deduction
Qualifies commercial building retrofits and new construction for federal tax deductions up to $5.00+ per sq. ft. by reducing total building energy and power costs relative to reference standard baselines. Modeled via qualified software (DOE EnergyPlus / eQUEST).
IRA Section 45L Multi-Family Tax Credit
Provides up to $5,000 per dwelling unit for multi-family buildings certified under the DOE Zero Energy Ready Home (ZERH) standard. Incorporating DWHR lowers source EUI sufficiently to satisfy national program certification thresholds without complex rooftop mechanicals.
LEED v4.1 / v5 BD+C Certification
Earns points under Energy & Atmosphere (EA): Optimize Energy Performance. The permanent, non-degrading nature of passive copper heat transfer delivers guaranteed lifecycle energy savings for verification in post-occupancy measurement & verification (M&V) audits.
Commercial Project Archetypes
Application Engineering & Operational Payback
Thermal performance models based on average commercial utility rates ($0.14/kWh electric, $1.10/therm natural gas):
Commercial 4-Inch Core Specifications (Series TD4)
Manufactured with heavy-gauge copper DWV core tubes and high-pressure potable coils. Outer drain ends are sized for standard shielded mechanical couplings (No-Hub):
Hydraulic Engineering Flexibility
Series Piping, Parallel Manifolds & Vertical Stacking
ThermoDrain units can be staged to match the specific pressure allowance and thermal lift requirements of the building:
Series Coil Piping
Max ΔT Lift
Piping outer potable coils in series forces total makeup flow sequentially through each coil. This increases fluid velocity, pushes the flow regime deeper into the turbulent zone (higher Reynolds number), and maximizes the convective heat transfer coefficient ($h$) for higher outlet preheat temperatures. Best suited for standard 3/4" nominal flow rates with robust municipal supply pressure.
Parallel Manifolds (1" to 2"+ Mains)
High Flow Capacity
Enables seamless connection to 1", 1-1/2", and 2" primary water service mains. By branching the main header into parallel 3/4" coil runs using reverse-return (Tichelmann) piping, the total flow volume is divided. This keeps potable velocity within standard engineering limits (5–8 ft/s) and maintains total loop pressure drop strictly ≤ 2.5 psi across flows from 8 to 40+ gpm.
Vertical Drain Stacking
Extended Drop
Where vertical riser drops permit (e.g., parking garages, basements, or multi-story mechanical chases of 9 to 12 ft), two units can be stacked vertically on the same drainage stack with shielded couplings, effectively doubling annular film contact time without expanding the horizontal footprint.
Plumbing Code Precaution: Regardless of series or parallel orientation, preheated potable discharge must route exclusively to the primary water heaters or storage tanks. Preheating direct cold feeds to thermostatic mixing valves is strictly prohibited.
Commercial Procurement & Distribution
ThermoDrain® equipment is available via national wholesale supply contracts. Invoicing is conducted through existing mechanical contractor commercial trade accounts:
Ferguson Enterprises • Winsupply • Keller Supply Company • Hajoca Corporation • The Granite Group