grabowski
5184014a2d
Press cooling return (60 C) feeds heat pump into boiler feedwater; waste heat runs label oven and HVAC dehumid reheat; solar thermal preheat; steam accumulator; boiler does only the final lift. Heat pumps for the final 180 C steam and ground-source in tropical Thailand both ruled out with reasoning; northern Thailand LPG tank context documented
125 lines
6.8 KiB
Markdown
125 lines
6.8 KiB
Markdown
# Sustainability
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Two commitments are fixed design requirements for this plant, not aspirations
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to be traded away during engineering: run on as much renewable energy as
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possible, and discharge no contaminated water. Both are decisions we can
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actually make, because the two biggest utility systems (steam and cooling)
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are explicitly excluded from the Newbilt scope and will be sourced and
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installed locally in Thailand. That gives us a free hand to spec them green
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from day one.
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## Renewable energy: large solar installation
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The pressing machinery itself is a modest electrical load: 32 kVA connected,
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~21 kW average for a full Duplex line. The real energy demand sits in the
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utilities around it, above all the steam generator (400 kg/h saturated steam
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at 10 bar / 180 °C) and the 250 kW cooling system.
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- A large rooftop/ground PV installation is planned. Northern Thailand's solar
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irradiance is favorable, and daytime-heavy production shifts align well with
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PV output.
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- The chosen hardware direction: multiple large **Deye** three-phase hybrid
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inverters (30 to 80 kW class, parallelable up to 10 units) paired with a
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**Gobel Power** high-voltage LiFePO4 battery stack at **271 kWh** (15
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stacked 18 kWh packs, LFP 314 Ah cells, rated 8000+ cycles). Deye is an
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officially supported protocol on the Gobel BMS, and Deye has established
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Thai distribution. Two engineering checks are open: matching the battery
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rack's DC voltage window to the specific Deye model (a full 15-pack rack
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can exceed the 800 V window of the smaller Deye series), and obtaining
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Gobel's safety certifications (not published) for a Thai commercial
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install. At 271 kWh the stack is a peak-shaving and ride-through buffer,
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not full off-grid autonomy, against loads like the 250 kW cooling system.
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- The machine load and cooling system are straightforward PV targets.
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- Steam is the open engineering question. Options under evaluation include an
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electric boiler (maximizes the solar share), a biomass boiler (locally
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abundant fuel), and solar-thermal pre-heating of boiler feedwater. No
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technology choice has been made yet; it will be driven by honest numbers on
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load profiles, storage, and grid backup, not by what sounds greenest.
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- Whole-factory HVAC (continuous temperature, humidity, and PM control, see
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[facility systems](facility-security.md)) adds a major tropical-climate
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load on top of process cooling and must be part of the PV and battery
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sizing.
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- System sizing (kWp, storage, grid-connection model) is open until the site
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is chosen.
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### Energy efficiency architecture: recover before generating
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The deepest efficiency in this plant comes from its own thermodynamics: the
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steam's job is to heat the molds, and the cooling water's job is to remove
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that same heat again, so roughly 98% of the 250 kW cooling load is heat
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leaving the press molds, put there almost entirely by the steam, and the
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press cooling return exits at ~60 °C. That
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warm return is a premium heat source, and the architecture is built around
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reusing it before generating anything new:
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- **Feedwater heat recovery**: a water-to-water heat pump lifts the 60 °C
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press cooling return into boiler feedwater at 90 to 95 °C. Each kWh it
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consumes does double duty: it cuts the boiler's work and removes load from
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the chiller at the same time. Together with condensate return, this saves
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roughly 10 to 15% of steam energy while shrinking the cooling system.
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- **Waste heat for low-grade consumers**: the label dry oven and HVAC
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dehumidification reheat (the 35 to 60% RH spec means air is cooled below
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dew point and reheated continuously) run on recovered press heat instead
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of fresh electricity.
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- **Solar thermal feedwater preheat**: flat-plate or evacuated-tube
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collectors reach 60 to 90 °C trivially in the Thai sun; cheap, proven, and
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stackable with the heat pump recovery.
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- **Steam accumulator**: the presses draw steam in bursts, so an accumulator
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(already a Newbilt option) lets a smaller boiler ride the peaks.
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- **The boiler only does the final lift**: whichever technology is chosen
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(electric, LPG, or biomass), it supplies just the last step to 180 °C /
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10 bar from already-hot feedwater.
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Two honest exclusions, checked and ruled out:
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- **Heat pumps cannot make the final steam**: commercial steam-generating
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heat pumps top out around 120 to 165 °C at lower pressures than the fixed
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Newbilt spec of 10 bar / 180 °C; hybrid heat-pump-plus-compression systems
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exist as industrial pilots, but core utility reliability is the wrong
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place to pioneer.
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- **Ground-source (earth temperature) does not work in tropical Thailand**:
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the ground sits at 28 to 30 °C year-round, far too cold to be process heat
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and warmer than the 20 to 25 °C cooling loop wants, so boreholes help
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neither side. That budget is better spent on PV panels.
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Fuel-side context for the boiler choice: there is no natural gas pipeline in
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northern Thailand, so gas firing means an on-site bulk LPG tank (roughly 2.5
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to 5 tonnes, with hazardous-storage separation distances and licensing), and
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diesel means a fuel tank with price exposure. The electric and biomass paths
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avoid a fossil tank on the property entirely, which matters for both the
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sustainability commitments and the BOI story.
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## Zero contaminated water
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The reference process schematic shows a conventional open "dirty water"
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cooling loop. We will not build it that way.
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- Cooling (up to 250 kW, 220 l/min peak, roughly 98% of it mold cooling) will
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run as a closed loop with a cooling tower/chiller, so process water is
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recirculated rather than discharged.
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- Steam condensate will be recovered and returned to the treated feedwater
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cycle instead of being dumped.
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- The planned in-house galvanics line (silvering and stamper electroforming)
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involves plating chemistry: silver solutions and nickel baths. This is the
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hardest part of the zero-discharge commitment. Rinse water will need
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closed-loop treatment and metal recovery, designed in from the start rather
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than retrofitted.
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- Solvent handling (flagged in the site requirements) will be contained and
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disposed of as controlled waste, never via wastewater.
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- Target: no process-water discharge to the local environment. Detailed water
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balance and treatment design are pending site selection.
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## Materials
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The plant design already includes a PVC recycling loop: an in-house grinder
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returns trimmings and rejects to the extruder, with the standard feed mix at
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80% virgin / 20% recycled compound. Record scrap becomes feedstock, not
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landfill.
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For the virgin compound itself, the preference is **local (Thai/regional)
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PVC sourcing if the quality meets vinyl-record specifications**. The current
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supplier list (2021) is almost entirely European, with one US option;
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qualifying a local compound would cut shipping distance, cost, and the
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carbon footprint of the feedstock. European suppliers remain the fallback
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where quality demands it.
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