How the model reads against published data. Every row is a comparison a test in the code makes and fails on if the number moves — the readings here are those tests' readings, not a marketing summary of them. The publications themselves are on Where the numbers come from.
| What | Against | Points | Reading | Held by |
|---|---|---|---|---|
| Fin-and-tube coil model (Elmahdy & Biggs air side, Gnielinski/Dittus-Boelter bracket water side, computed fin efficiency, contact resistance) | Carrier 28B-3PD rating matrix — rows 4/6/8/10 × three circuitings × 8/11/14 fpi at one stated condition | 36 | total capacity RMS 1.21 %, worst 2.0 %; sensible RMS 0.98 %; leaving RH within 0.5 points on average (re-read 27 Aug on the corrected saturation line, calibration 0.81) | the_coil_model_against_carriers_rating_matrix |
| Coil model, wavy fin | Colmac Engineering Bulletin 5050 worked selection (ARI 410 geometry) | 1 | within 5 % of the published duty at a fin enhancement of 1.20, inside the literature's 1.1–1.3 band | the_coil_model_against_colmacs_published_selection |
| Dry-coil Colburn j-factor and whole-coil UA | Taylor 2004 (Georgia Tech) measured plain-fin coils | 38 + 1 | j +13.3 % mean against 38 measured points (inside the 3–18 % contact resistance the thesis folds into its own j); UA 0.6380 against a measured 0.6327 kW/K — 0.8 % (0.14 % at the pre-27-Aug calibration) | the_colburn_j_against_measured_dry_coil_data, the_coil_model_against_a_measured_dry_coil |
| Water-side pressure drop, tubes and headers | Colmac's published tube-side figure; Carrier 28BC's thirteen assembly drops | 1 + 13 | 14.6 ft of water against a stated 14.5 with nothing fitted; the thirteen assembly drops within ±12 % (eleven inside ±7 %) | the_water_side_pressure_drop_matches_colmacs_published_figure, the_header_term_closes_carriers_assembly_drops |
| Cooling-tower model (Braun enthalpy-basis ε-NTU, one fill exponent) | Marley Aquatower performance tables, 13 models × 49 conditions | 615 | mean +0.004 K, RMS 0.275 K, worst 0.72 K on cold-water temperature | the_tower_model_against_marleys_performance_table |
| Cooling-tower model, zero fitted parameters | EVAPCO LPT bulletin, 43 models × 20 metric conditions, published airflows | 856 | mean −0.08 K, RMS 0.116 K, worst 0.41 K — NTU from the vendor's own Eurovent column, the shipped exponent | the_tower_model_against_evapcos_lpt_table |
| Compressor maps converted from the vendor's own rating database | Copeland nomenclature (ZP104 is 104 kBtu/h at 45/130 °F, …) on thirteen basis sets; capacity per displacement within each family | 4 776 maps | every basis median within 3.2 % of the nomenclature; the vendor's polynomial substituted exactly, never refitted | the_copeland_maps_reproduce_their_nominal_capacity, the_copeland_conversion_is_the_vendors_polynomial_in_si |
| Part-load interpolation between published compressor steps | Danfoss VZH088's own thirty-term polynomial in (te, tc, speed) | the envelope between 16 steps | 0.04 % mean, 0.21 % worst between the knots | steps interpolation guard (components.rs) |
| Fan power from a published power curve through the fan laws | ebm-papst RadiPac K3G450-AQ24-90 measured points | 4 | all four reproduced; a constant efficiency mis-stated them by 19–100 % | the_ebmpapst_listing_reproduces_its_measured_points |
| Circulator curves read from vendor charts | Grundfos MAGNA3 data booklet P1 tables; Wilo Stratos MAXO datasheets | 12 listings | curve tops within 3.5 % of each Grundfos page's P1 table; every Wilo listing under its datasheet's P1(max) | the_circulator_curves_reproduce_their_own_rating_points, the_wilo_listings_sit_under_their_datasheets_p1_max |
| Evaporative media effectiveness | Munters CELdek 7090/7060 2022 curves | curves at 100 and 150 mm | the vendor's curves carried on the listings; the generic polynomial they replace reads 3–13 points low | the_munters_listings_carry_the_vendors_curve_not_the_polynomial |
| Heat-pipe recovery effectiveness | ACT WAHX selection tool on the 1473×1100 coil | 3 sizes | within 1 point of ACT's selection | ACT listings guard (catalog) |
| Condenser fan staging | AHRI 340/360-2022 Appendix G Example 8 | 1 | 650 W → 325 W reproduced | fan bank staging guard (components.rs) |
| Water properties | IAPWS-IF97 region 4 official verification values | the published table | pinned exactly | psychro.rs IAPWS tests |
| Moist-air saturation line (IAPWS-IF97 water line with Buck's 1981 enhancement factor) | ASHRAE Fundamentals Ch. 1 Table 2 (SI), saturation humidity ratio at 0, 10, 20, 25, 30 and 40 °C | 6 | within 0.1 % at every point — a flat 1.015 factor had put the line about 1 % high until 27 Aug | the_saturation_line_matches_ashrae_table_2 |
| Refrigerant properties without the CoolProp library | CoolProp itself | the R410A saturation range | validated curve fits, hfg within 1.8 % | hvac-props fits tests |
A coaxial (pipe-in-pipe) exchanger is modelled from tube length and diameter, which its makers do not publish — they rate a kW at a state — so it is unanchored until a rated point can be declared. A plate exchanger's counterflow relation is the textbook one and its rated point round-trips exactly, but no maker's selection has been checked against it yet. A centrifugal chiller's part-load curve is not modelled; the campus plant runs four fixed-speed scrolls as a declared stand-in. Building-level results are estimates: the zone model is a deliberately transparent 1R1C balance, and the worked cases say where each one leaves something open.
Results are engineering estimates from catalog data and published correlations; a catalog entry's certification badge is the supplier's own claim unless marked verified.