Walk into a typical Philippine commercial bakery at three in the morning, and you'll see two rooms running back-to-back. In one, the proof boxes are pulling electric resistance to hold the dough at 44 °C / 85% RH. Twenty metres away, an air-cooled chiller is hammering away at the cooling hall, hauling heat off freshly baked bread and dumping it onto the loading-dock roof.
The proofer is buying heat. The chiller is throwing it away. It is the same heat. The plant is paying for it twice, on the same Meralco bill, every hour it runs.
1. Bakery proofing needs heat (40–46 °C / 80–90% RH). Bakery cooling needs cold (20–25 °C / 60–70% RH). Both run simultaneously, every shift.
2. Conventional plant uses an electric resistance heater (COP 1.0) for proofing AND an air-cooled chiller for cooling. The chiller dumps the same heat the proofer is about to buy.
3. A simultaneous-heating-and-cooling (SHC) heat pump moves the heat from the cooling AHU straight to the proofing AHU. Combined COP 6–8.
4. Worked case: 100 kW thermal load, 16h/day, Meralco GP April 2026 tariff — ₱22,400/day → ₱4,480/day (~80% reduction). With iVOLT solar, ₱1,500/day (~93% reduction). Payback 18–36 months.
The two thermal loads, side by side
A modern Philippine bread plant has narrow biochemical tolerance bands on both ends of its process.
On the proofing side, dough is alive. Yeast metabolises sugars at a rate that doubles every 10 °C, so the proof box has to hold within a 5 °C window or the dough either over-proofs (protease blowout, cell rupture, collapse) or under-proofs (dense, undersized, irregular). The proof environment is 40–46 °C dry-bulb, 80–90% RH — high enough heat and humidity to keep the dough biologically active without crusting the surface.
On the cooling side, bread coming off the oven at 95–98 °C internal core temperature has to be cooled to 32–43 °C before slicing and packaging. The crumb is setting, the starch is crystallising, and roughly 2–3% of loaf mass is released as water vapour during the cool-down. The cooling hall has to remove that latent moisture and hold around 20–25 °C / 60–70% RH continuously. Above 43 °C at packaging, internal vapour condenses inside the sealed polyethylene bag; water activity climbs past 0.80 and Rhizopus or Penicillium colonies germinate within 48–96 hours. Below 32 °C, the loaf becomes brittle and stales prematurely.
Both halls run simultaneously, every shift, every day. The thermal demand from the cooling hall is roughly equal to the thermal demand the proofer is buying — the energy hauled off cooling bread is almost exactly the energy needed to keep new dough proofing. A conventional bakery plant cannot share that energy across the two duties; the chiller dumps and the proofer buys.
What the conventional plant costs
Take a typical mid-size Philippine commercial bakery — a 100 kW combined thermal load (proofing box + DHW + cooling-hall reheat) running 16 hours a day, 6 days a week. At the Meralco GP April 2026 tariff of ~₱14/kWh blended (plus ~₱700/kW combined demand charges), the daily energy cost depends entirely on how that 100 kW of useful heat is delivered:
| Configuration | Daily thermal energy | Reduction |
|---|---|---|
| Electric resistance (COP 1.0) | ₱22,400 | baseline |
| Standard heat pump (COP 3.5, single-mode) | ₱6,400 | −71% |
| Karnot SHC heat pump (combined COP 5.0) | ₱4,480 | −80% |
| + 15 kWp iVOLT solar bolt-on | ₱1,500 | −93% |
Annual saving on the heating side alone: ~₱6.5M. Monthly demand-charge saving: ~₱56K. Per-facility payback at industry F&B benchmarks: 18–36 months.
Why SHC wins on coupled bakery loads
The reason SHC wins is structural. Every other heat-delivery technology can only do one job at a time. A boiler heats. A chiller cools. A standard heat pump does either heating OR cooling. A bakery needs both at once, so a single-mode machine has to do the work twice.
Look at the combined-COP comparison:
| Plant type | What it does | Combined COP |
|---|---|---|
| Electric resistance heater | Heating only | 1.0 |
| Air-cooled chiller | Cooling only | 2.5–3.5 |
| Standard heat pump | Heat OR cool | 3.0–5.0 |
| Karnot SHC heat pump | Heat AND cool simultaneously | 6.0–8.0+ |
The Karnot SHC combined COP of 6–8 isn't a marketing number. It's the arithmetic of one compressor input doing two useful jobs in the same cycle. One kilowatt of compressor input delivers approximately 3.5 kW of cooling AND 4.5 kW of heating at the same time. Combined: 8 kW of useful thermal work per kW of electricity.
The architecture: iHEAT + dual iSTOR + twin AHU + iVOLT
The Karnot bakery system has four parts:
- iHEAT R290 reversible heat pump — the SHC engine. Sealed outdoor monobloc. Extracts heat at the cooling-hall AHU coil, runs it through the compressor, and delivers it to the proofing-hall AHU coil in the same cycle. R290 (propane) holds COP above 3.0 across the full Philippine ambient range; GWP of 3, no Kigali phasedown clock.
- Two iSTOR phase-change tanks — one hot tank at 44 °C, one cold tank at 22 °C. Patented PCM, natural fluids sourced in the Philippines. They buffer minute-by-minute imbalance between cooling and proofing demand. When one side spikes, the corresponding iSTOR tank discharges to the AHU; the heat pump doesn't have to short-cycle, and neither hall sees an interruption.
- Twin Karnot AHUs — one delivering 40–46 °C / 80–90% RH to the proof boxes on a humidistat, one delivering 20–25 °C / 60–70% RH to the cooling hall with HEPA filtration and positive pressure (CIBSE Guide B2 — flour-dust and Aspergillus / Rhizopus spore exclusion).
- iVOLT solar + Li-ION — zero-export rooftop PV + Karnot inverter + LiFePO4 battery. Sized to carry the SHC loop through daylight hours. Pushes the bakery's thermal energy cost from ~₱4,480/day on the grid-only SHC to ~₱1,500/day with solar in front of it.
Compliance: ASHRAE, CIBSE, EN 378, IPMVP
Bakery climate plant has to satisfy three families of standard simultaneously — refrigeration design, refrigerant safety, and food-safety airflow. Karnot designs to all three from day one:
- ASHRAE Refrigeration Handbook Ch. 41 (Bakery Products) sizes the cooling-hall evaporator to handle the 2–3% latent moisture released during bread cool-down. Ch. 23 (Refrigerated Facility Design) governs vapour-barrier integrity inside both halls — critical for the Philippine wet season, to prevent interstitial condensation and panel rot.
- EN 378 / ASHRAE 15 / IEC 60335-2-89 govern R290 charge limits in occupied spaces. R290 is classified A3 (highly flammable). Karnot uses an indirect monoblock architecture — the entire R290 circuit lives in a sealed outdoor unit, and only safe water/glycol enters the bakery building. This permits charges up to ~80 kg per the IEC indirect-monoblock provisions, with no R290 ever entering an occupied space.
- CIBSE Guide B2 (Ventilation & Ductwork) governs airflow to the cooling halls — discharge velocity capped to prevent crust dehydration. HEPA filtration on supply air keeps Aspergillus and Rhizopus spores out. Positive pressure in the cooling hall blocks flour-dust infiltration from raw-ingredient zones.
- IPMVP Option B (continuous retrofit isolation) — dedicated kWh sub-meters on the heat pump plus continuous space T/RH datalogging. Mathematically isolates the system boundary so the combined COP is verifiable — bankable for ESCO contracts, CECO reporting under RA 11285, and PFRS S2 sustainability disclosures.
The conventional bakery plant isn't just inefficient — it's the wrong architecture. By matching the architecture to the load (simultaneous heating and cooling from one heat-pump loop, buffered by phase-change storage on both sides, with solar electricity in front) we eliminate the structural waste — we don't trim around it.
How a bakery project starts
One free site survey. Our engineers spend a day on site, datalog the proof-box and cooling-hall temperatures and humidities through a full bake cycle, pull 12 months of utility data, and model the combined thermal load using the ASHRAE Heat Balance Method per Ch. 41. Within 14 days you receive a one-page indicative report — load calculation, recommended iHEAT + dual iSTOR + twin AHU + iVOLT sizing, indicative capex range, projected annual saving at today's Meralco tariff, payback period, and CO2 avoided.
No procurement triggered. No obligation. The output is yours to keep regardless of whether you proceed.
Want a worked case for your bakery?
Book a free site survey. We model the load using ASHRAE Refrigeration Handbook Ch. 41, size the iHEAT + dual iSTOR + twin AHU + iVOLT package, and come back with a one-page indicative proposal — no commitment.
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