The order to investigate for a fired boiler (biomass such as rice
husk, or LPG): first a flue-gas economizer, second as much clean, hot
condensate back to T-1 as possible, third the heat pump HP-1 where the
press return has enough heat and the combined heating and cooling
economics justify it.
- Diagram: new ECON-1 (option, fired boilers only) between the feed
pumps and the boiler manifold, with a bypass for an electric bank and
the flue-gas path from the boilers; feed in 90 to 95 C, outlet and
stack temperature are vendor figures. HP-1 is now drawn as an option
and labelled the third measure. AT conductivity on the condensate
return to T-1; off-spec condensate goes to the warm tank.
- Found in Newbilt's offer 240620-04: steam and cooling water share the
mould channels, with one steam/water outlet valve and steam trap per
mould, so the condensate is only as clean as the cooling loop. Noted
in the T-1 detail, sustainability.md and as a Newbilt RFQ question.
- With most condensate returned (about 15 % flashes at atmospheric
pressure, estimate) the feed tank needs only a fraction of the ~70 kW
that heating all make-up takes, so HP-1 may not pay.
- RFQ: economizer outlet feed and stack temperature, corrosion limit,
pressure drop; rice husk ash is high in silica and abrasive, so
fouling, cleaning, wear protection and a bypass.
- sustainability.md: the order, before the exclusions. biomass.md: new
"Recovering heat at the boiler".
Checked headless (scripts/pw_sc_check.py): 33 boxes, 20 tags, no
overlap or overflow, no unstyled pipes, no card or page overflow at
1600, 1258 and 390 px in all four cases, every box opens its detail, no
errors.
New page docs/steam-cooling.html (site /demos/steam-cooling/): the
utility plant as a clickable process diagram. Steam side: raw water,
softener and dosing, feed tank with heat-pump feedwater recovery, feed
pumps, a bank of two 500 kg/h boilers (third for N+1 as an option),
separator and metering, optional accumulator, blowdown, the 10 bar
header with a valved, metered branch and trap per press, drip legs and
condensate return. Cooling side: Newbilt's press outlets are open (max.
2 bar), so returns drain to a warm tank, pass the heat pump, an optional
dry cooler and a plate heat exchanger to a cold buffer tank, and VFD
pumps feed the 20 to 25 C header at ~10 bar to every press, the
extruders and the central hydraulic oil cooler; the chiller loop
(three 250 kW air-cooled modules at 40 C ambient, fourth as option) stays
closed and clean. Galvanics cooling (12 to 20 C) is a separate circuit.
Operating cases (launch, Duplex system 1, five presses, one module down)
show demand against installed capacity; design basis with sources,
equipment schedule, RFQ questions. Static SVG, no per-frame work.
Design basis at Newbilt's per-machine figures: steam 750 to 900 kg/h,
cooling 652.5 kW (625 presses, 15 extruders, 12.5 hydraulics), 305 to
540 l/min circulating. Also found: Newbilt's 53 l/min at ~60 C out is
~140 kW, above its 125 kW peak; listed as a re-quote question.
Re-based in the same commit:
- scale.md: electrical table (chiller bank ~210 to 325 kW electrical,
plant peak ~430 to 700 kW, ~950 to 1,330 kW with electric steam),
grid 800 to 1,000 kVA (1,250 to 1,600 with electric steam, Schedule
4 past 1,000 kW), tariff 4.5M to 6.8M THB/yr, battery ~1 h of chiller
peak, boiler and chiller banks, biomass up to ~550 t/yr at 1.5 M
records, utilities money line.
- sustainability.md, biomass.md: same figures; electric steam 5.2M to
6.0M THB/yr mature, 1.6M to 1.8M early; fuel saving 4.0M to 5.4M.
- utilities CSV: boiler bank, chiller bank with HX and tanks, softener
and loop treatment re-sized; baseline 23.98M-41.63M -> 30.07M-51.33M.
- total-investment.md: re-size as an added-scope row (+185k / +294k
USD); headline 4.7M to 8.9M unchanged until the investment re-base.
- pressing-line, equipment-suppliers, facility-security, fleet
calculator (boiler 1000 kg/h, chiller 750 kW), plant page detail
texts; README, landing page, build.sh.
No public price index exists; DEDE lists buyers, not prices. Reported
market prices: fresh chips 1,350-1,800 THB/t (LH Bank, Mar 2026),
rubberwood firewood >1 THB/kg farm gate (OIE RIU 2026, doubled since late
2025), corn residue 2 THB/kg (Sunsweet, Mae Chaem), rice husk ~1.5 THB/kg,
pellets 3,000-5,000 THB/t. Planning price 1.35-2 THB/kg delivered, so the
mature fuel bill is ~0.6M-1.2M THB/yr (was 0.35M-0.8M): still a quarter
to a tenth of electric steam. Prices follow diesel; Ratch Pathana's Pa Sak
(Lamphun) buying centre is the local price-setter. Sources filed under
docs/finance/biomass/; sustainability.md and README follow.
PEA tariff schedule (May 2023 onward, still current) filed under
docs/finance/pea/; Ft 0.1623 THB/kWh for Sep-Dec 2026 from the PEA Ft page.
The plant falls under Schedule 3.2.2 (Medium General Service, TOU, 22 kV).
New section in sustainability.md: blended ~3.81 THB/kWh for two-shift
production plus 132.93 THB/kW demand charge; electric steam ~4.7M-5.5M
THB/yr at maturity against ~0.35M-0.8M of biomass fuel; self-consumed PV
worth ~3.7 THB/kWh (~4.5-7 yr payback); solar thermal not recommended;
the battery earns little from TOU arbitrage or peak shaving. biomass.md,
scale.md, the utilities CSV note and the README follow.
Own land yields ~80-135 t/yr vs ~350-400 t/yr mature demand; forestry
classification check gates everything; staged electric-first path with
coppice planted now for the expansion-phase biomass boiler
grabowski