From 5184014a2dd9a1879cca7d82f67866ac4e3d466a Mon Sep 17 00:00:00 2001 From: grabowski Date: Fri, 17 Jul 2026 17:09:35 +0700 Subject: [PATCH] Add energy efficiency architecture: heat recovery before generation 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 --- docs/sustainability.md | 47 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/docs/sustainability.md b/docs/sustainability.md index eb3707b..cf4413b 100644 --- a/docs/sustainability.md +++ b/docs/sustainability.md @@ -42,6 +42,53 @@ at 10 bar / 180 °C) and the 250 kW cooling system. - System sizing (kWp, storage, grid-connection model) is open until the site is chosen. +### Energy efficiency architecture: recover before generating + +The deepest efficiency in this plant comes from its own thermodynamics: the +steam's job is to heat the molds, and the cooling water's job is to remove +that same heat again, so roughly 98% of the 250 kW cooling load is heat +leaving the press molds, put there almost entirely by the steam, and the +press cooling return exits at ~60 °C. That +warm return is a premium heat source, and the architecture is built around +reusing it before generating anything new: + +- **Feedwater heat recovery**: a water-to-water heat pump lifts the 60 °C + press cooling return into boiler feedwater at 90 to 95 °C. Each kWh it + consumes does double duty: it cuts the boiler's work and removes load from + the chiller at the same time. Together with condensate return, this saves + roughly 10 to 15% of steam energy while shrinking the cooling system. +- **Waste heat for low-grade consumers**: the label dry oven and HVAC + dehumidification reheat (the 35 to 60% RH spec means air is cooled below + dew point and reheated continuously) run on recovered press heat instead + of fresh electricity. +- **Solar thermal feedwater preheat**: flat-plate or evacuated-tube + collectors reach 60 to 90 °C trivially in the Thai sun; cheap, proven, and + stackable with the heat pump recovery. +- **Steam accumulator**: the presses draw steam in bursts, so an accumulator + (already a Newbilt option) lets a smaller boiler ride the peaks. +- **The boiler only does the final lift**: whichever technology is chosen + (electric, LPG, or biomass), it supplies just the last step to 180 °C / + 10 bar from already-hot feedwater. + +Two honest exclusions, checked and ruled out: + +- **Heat pumps cannot make the final steam**: commercial steam-generating + heat pumps top out around 120 to 165 °C at lower pressures than the fixed + Newbilt spec of 10 bar / 180 °C; hybrid heat-pump-plus-compression systems + exist as industrial pilots, but core utility reliability is the wrong + place to pioneer. +- **Ground-source (earth temperature) does not work in tropical Thailand**: + the ground sits at 28 to 30 °C year-round, far too cold to be process heat + and warmer than the 20 to 25 °C cooling loop wants, so boreholes help + neither side. That budget is better spent on PV panels. + +Fuel-side context for the boiler choice: there is no natural gas pipeline in +northern Thailand, so gas firing means an on-site bulk LPG tank (roughly 2.5 +to 5 tonnes, with hazardous-storage separation distances and licensing), and +diesel means a fuel tank with price exposure. The electric and biomass paths +avoid a fossil tank on the property entirely, which matters for both the +sustainability commitments and the BOI story. + ## Zero contaminated water The reference process schematic shows a conventional open "dirty water"